Lots of people can get palpitations, they can occur in totally healthy people. Some people notice theirs, and some don't.
Anxiety can cause palpitations, that is one of the general symptoms of severe anxiety. They can also be caused by stress too. If you have concerns, you can go to your physician and tell him or her about it and they'll look you over. But considering you are young, and if you are in generally good overall health, then you really don't have anything to be worried about.