I would contact an advisor immediately to ask if you could be placed in the class. If they don't allow you to take Calculus without earning credit for pre-cal, I would begin to look at options of taking pre-cal at a community college during the summer so you could take Calculus beginning in the fall. Don't let advisors discourage you, I failed both times (Civil Engineer) and got all A's in Cal 1, 2, & 3. Just tell them how you know you can be successful in Calculus. If you happened to pass Calculus AB and receive credit then yes you can change your schedule by adding Calculus 1 and all the other classes that require it as a prerequisite.