Well if you invested that money 3 years ago you would probably be rich now...
If you could live with possibility of loosing all the money you have put into bitcoins so far - then there's no reason to sell them...
Maybe in a year you'll be able to buy a new car or with that coins you bought this year.
Once again - if you can stand that risk (of loosing it all) don't sell. Just sit and wait...
If you can't sell them and never look back...
So far things are going good.
It's getting more and more adopted online as a form of payment, new services are being developed, it's getting more and more media attention...