It is the nature of investing that it is impossible to know for sure what is coming. Many think that we are in altcoin bubble, and yes, very soon there will be massive price drops. But there is also a chance that it is not a bubble, but a consequence of rising public awareness of crypto. There is also a chance that it is a bubble, but it still has many months to run.

Don't rely on strangers to tell you what will happen, it is not like you can blame them for any loss you might suffer.

Have not seen this analysis done anywhere, so I put together a page showing Value-at-Risk for BTC and ETH: http://coinrisk.info/
Professional asset managers use it all the time for risk management. It is also one of the tools to use when deciding how much to borrow when trading on margin.

I think the pump is easy to see - if you hear a lot about some coin, then it is being pumped, by definition.
One problem is that not every pump succeeds - sometimes even the best marketing campaign is not enough to convince people to buy. Another problem is that the dump starts without any notice, so there is no guarantee that you will get out in time...

100$ is not a big amount, so I assume you are not looking to grow it slowly and conservatively, but hoping for a quick 100x payout. I would say you won't get that in Bitcoin or Ethereum quickly, as those have already been hyped for years. You could try your luck with one of the new altcoins, if you can get in initially while few have heard about a certain coin, and then it somehow becomes popular, you will be looking at big gains.

The only problem is "somehow" bit - we cannot really predict which coin will become popular and which will wither away...  So it is a bit like playing lottery.