I want to take regular calculus during my senior year but I need a pre-calculus first how would I be able to do that?
First you have to talk to your school about what they will accept and the procedure to skip a class. S took a placement test at school and was able to skip pre-calc. There are many online options - Art of Problem Solving (AOPS) has online classes, or books if you want to self study, ALEKS is an online, self paced program (monthly fees), Khan Academy is free online to self-study. There are probably local classes to you as well.