@MYOS1634 IU accepts any transfer credit approved in the CTS database regardless of when it was taken. I came to IU as a freshman with 3 college courses and a bunch of AP. Indiana residents I know came to IU with 50+ credit hours since many Indiana classes are dual credit. They were Freshman for everything except the credit report and registration.
@TheInstitute OMG are you listening? Virtually nothing at IU will be as easy as high school, AP or not. Major-level science classes at IU are most certainly harder than your AP version. Only the science courses for non-majors will be relatively easy. Given your stats above, I would guess you are bright, but no genius. You will run into folks on this board and others at IU that blow away those stats. Do not come in overconfident and get surprised.
You can register for any class you like, as you build your schedule. Professors are almost always listed otherwise it’s Staff. Check out this thread to be ready for registration:
http://talk.collegeconfidential.com/indiana-university-bloomington/1661274-orientation-2014-tips-p1.html
Be aware that getting a popular professor can be tough since all but Freshman registration is based on how many credits you have. Because of this, coming in with AP and college transfer credits will help you get ahead of others in the registration priority list. I am in my 4th semester at IU right now but have Junior standing based on credits. I will graduate with far more than the required 120 hours.
Finally, you can’t really judge how hard something is at IU until you take it or talk to someone in detail about the class. Everyone is different and you just never know what will challenge you. Sometimes it’s the material and other times it’s the professor’s style.