This is great. Thanks for helping to educate those in your area.
Here are some additional thoughts on the questions you received:
- Is Bitcoin secured
That depends on what you mean by "secured". If you are asking if it is a certificate that represents some other form of tangible value (such as a stock certificate representing the value of a company, or a loan being secured" by collateral) then no. However, if you are asking if it has a robust and reliable security system preventing unauthorized access, then absolutely yes.
The software that runs the bitcoin system has been reviewed by thousands of people. There are no known cases of any breach of the network in over a decade and there are hundreds of billions of U.S. dollars worth of value being secured so we can pretty confidently say that there is plenty of incentive for someone to spend a lot of money trying. The fact that nobody has succeeded yet given that incentive is a strong indication that it is one of the most secure systems in the world today.
However, while the network itself is extremely secure, protecting the bitcoins belonging to any individual is the responsibility of that individual. The software that is used to access your bitcoins generally contains the keys (or secrets) that are used to manage that value. If an individual is careless with those keys/secrets then it is possible for an attacker to gain access to that information and use it to take/control that person's bitcoins. If you are going to manage your bitcoins yourself, it is therefore very important to protect those keys from being accessed by others through malware, hacking, phishing, or other scams.
Alternately, if you don't feel comfortable with your own ability to secure your keys, there are companies/services that will hold custody of your bitcoins for you and will manage the security for you. There is a risk in that option that the company/service you choose is either untrustworthy or incompetent. Everyone has to figure out their own risk tolerance and make their own decision as to whether they feel they can do a good enough job of protecting their keys, or if they feel they need to trust someone else to do it for them.
If you choose to manage your access yourself, there are systems available (such as hardware wallets, and cold wallets) to make that process easier for those that have accumulated an amount of bitcoin that they become nervous about securing.
and how do you earn from it?
Bitcoin is money. You "earn from it" the same way as you "earn from" any other money. You can create a product or provide a service and accept bitcoin as payment in exchange. You can beg for bitcoin and hope that some charitable person will give you some for free, you can attempt to steal or scam someone out of their bitcoin, or you can exchange one form of money (such as your local currency) for it. As the exchange rate between bitcoin and your local currency changes over time, there is an opportunity to exchange back and forth acquiring your local currency when it is stronger and acquiring bitcoin when your local currency becomes weaker in comparison. The historical trend over the past 10 years has been for the bitcoin currency to increase in strength quite a bit over all local currencies. Therefore, it has historically been beneficial to acquire as much bitcoin as one can afford to risk, and then over time end up with increasing purchasing power as the bitcoin exchange rate increases. There is no guarantee that this will continue to be true, and even if id does continue to be true for many more decades there isn't any guarantee that it will be true over any arbitrary time period (hours, days, weeks, months, years, etc).
- Is Bitcoin only for young people?
As I said, Bitcoin is money. Therefore, bitcoin is for anyone that uses money. It does currently require some access to (and comfort using) technology (internet, software, computer or smartphone, etc), though you may be able to get a technology savy person in your family or household to assist you with acquiring and/or using some if you aren't comfortable doing so on your own.
- Can someone manage it for you (since they are always kind of busy)
As mentioned earlier, this is a risky thing to do. There have been many cases in the past of people trusting someone (or some service) to manage their bitcoin for them, and then after a while that trusted person or service vanishes with all the bitcoin wealth accumulated by all the people for whom they were managing bitcoin. There also have been cases of incompetent people or services losing bitcoin to hackers or scammers. Much like physical cash, if you give access to your bitcoin and someone runs off with it, the ONLY way to get it back is to find them and force them to give it back (for example through the threat of violence or through lawsuits).
- Asked about the legality of Bitcoin
Your answer to this one was very good. It is important to understand that every jurisdiction is different and that the vast majority of jurisdictions in the world have no laws AGAINST acquiring, holding, spending, or selling bitcoin itself. If you are buying or selling very large quantities and/or exchanging with a large number of people, then some jurisdictions in the world might require you to have some sort of money service business license or comply with various anti-money-laundering processes.
-what is the least amount you can start with?
I exchanged $0.01 with someone once, but since there is a small transaction fee involved in sending the bitcoin from one person to the other that will generally be a silly idea. Before acquiring, figure out what fees you're chosen method is likely to incur. I'd generally suggest trying to keep the total fees (transaction fees, exchange fees, etc) below 1%. So, if the sum of all the fees is likely to be $0.10, then $10 is a reasonable starting point.
More important is to figure out what your personal risk tolerance is. The exchange rate between bitcoin and local currency changes all the time, and many times that exchange rate will spend a significant amount of time at a level where the market rate of the bitcoin you own is significantly less than you exchanged for it. If you spent $10 acquiring your bitcoin, and the exchange rate drops such that the market value of that bitcoin is only $4.70 for a year or two, it might be a bit frustrating, but you won't likely be devastated by it.
On the other hand, if you've saved up $8,000 that you were planning on spending on college tuition next year, and you decide to sink it ALL into bitcoin. It might be very upsetting if the exchange rate drops shortly thereafter to a point where the market value of your bitcoin is only $3,100, and even more upsetting if it doesn't recover above $3,600 for a few years.
-what are the advantages of being on bitcointalk and how to be a member?
Like any forum, there is a lot of nonsense on the bitcointalk forum along with some scams. Verify anything you learn there, and take the time to figure out who generally gives good information. There are, though, many people active on the forum with many years of experience assisting others with learning. It's a great place to share thoughts, concerns, ideas, and to gain knowledge.
- Differences between wallet and exchange.
An "exchange" is a person/company that provides a way for those who have local currency (and want to acquire bitcoin) to connect with those who have bitcoin (and want to acquire local currency). In most cases, the exchange handles the transfer of the funds (bitcoin and local currency) between the individuals, and many times does so without any need for those individuals to even know who the other is. To facilitate this, then generally require that you (at least temporarily) give them control over the amount of value you want to exchange (either of your local currency or of your bitcoin depending on which you have and which you are trying to acquire). There is some risk involved in this, so you want to be careful choosing the service that you'll use. If you're comfortable enough with the technology and process, there are some peer-to-peer exchanges that reduce the amount of control you need to turn over.
A "wallet" is the software (or in some cases hardware) that you use to manage access to your bitcoins. It is where the keys/secrets are stored that give you control over your bitcoins. It provides you a view of how much bitcoin you control. It provides a method for sending transactions. It provides a set of "addresses" you can tell to others so that they can use those addresses to send you some bitcoin.
Some exchanges or services that take custody of your bitcoins for you will provide you with an "account" in their system that you can use to see how many bitcoins they are managing for you and which you can use to tell them where you'd like them to send some bitcoins on your behalf. Some of those services even call these accounts "wallets". They are not the same as an actual bitcoin wallet though.