| Hi,
If you're undecided between 15a and 16, I strongly recommend trying out 16. In fact, in the first day of 15a, they recommend that anyone who is remotely considering 16 try it out. You don't have to sign up for anything, so if you find it goes over your head you can switch to 15a the second week (you won't miss anything important- it's what I did).
Having said that, 16 is an incredibly difficult course, so don't feel bad at all if you decide on 15a. But don't be scared off if you like it!
17 and 20 are both quite difficult, and a score on the AP doesn't really tell that much. It depends whether you're interested in biology and chemistry (17) or physics and chemistry (20). So for you, 20 might be a better fit. |