Can i start doing ballet again at 15?

I took 4 years of ballet as a little kid then stopped and did twirling for 3 years and now im in Color Guard. I do guard year round and the group i am involved in is kind of intense. We usually have a 2 hour dance block in the mornings where we do basic ballet and some intermediate things. We also do intermediate levels of across the floors. I'm really interested in starting ballet again. Would I take a beginner class or an intermediate class? Would i be able to go en pointe after awhile or no? Would i take an Adult beginner class? Your help is greatly appreciated !!!!