While I wait for a POS to coin in so I can show how that displays I will show how to turn on coin control and show coin age for those that don't know how to set it up.
Open your wallet up and click on settings then options
In the window that opens up select Display and then put a check in the check-box for 'Display Coin Control Features'
Then click ok and close that window
Thats it, coin control is now enabled as long as you are using version 1.1 Wallet
Now to see your coin age click on the send button followed by the 'inputs' button that now comes up
The coin control window will now open and let you see the age of your coins.
POS starts once the coins have been in your wallet for more than 30 days.
Cash creates a new block roughly every minute (It can be a bit slower or faster so its not exact) so for the coins to be 30 days old 43,200 blocks must of been created since you received them.
Look at the image below and its a small sample from my wallet with the youngest coins only having 5438 confirmations with the oldest having 41507 confirmations, so none of these are old enough to be used for POS, with the oldest being 1693 confirmations (minutes) (28.2 hours) from reaching 30 days.
Once a coin reaches 30 days age it doesn't immediately stake, and sometimes it does stake but someone else's wallet also creates a stake and only one will be excepted into the block chain so if they beat you, yours will never confirm. But don't worry you haven't lost anything, it will just try again until you do get a stake.
Also coin age can go out to 90 days, so if you go off-line for 90 days and then come back online you won't loose any interest just instead of it being 30 days worth of 10% PA it would be 90 days worth of 10%PA.
I'm pretty sure though if its longer than 90 days you will start to loose interest.
I'll post up what the coins look like in your wallet after you have earned POS when I next earn a POS