I wear contacts now (I'm 16). I've needed corrective lenses since I was 10 (4th grade). I wore glasses up until 7th grade when I switchesed to contacts to make it easier to play basketball.
It depends on how old you are, how responsible you are, what your parents and eye doctor think/feel, and how confortable you with touching your eye.
So, IMO, contacts are so much easier. Glasses just get in my way. I'm able to go about life as if I didn't need corrective lenses. BUT they can be annoying too. Like remembering to change them out and clean them every night. Also taking out them out before I go to bed (which I don't always) can be a hassel (all part of being responsible). Also they can bother your eyes if you get dirt or anything little on them or if they rip (which can happen especially if you sleep in them).
You need to be confortable with touching your eyes since the contact goes right on your eye. It may seem like there are more cons than pros, but I think the pros outweight them. I'm very athletic and my glasses would just get in the way.
One thing I really don't like about my contacts is that I have an astgimatism, but my contacts (I have to wear a certain kind due to my eyes themselves and my perscription) do not correct them...but I get over that fact.