Read posts there and see what other students who want to be majoring in theater have been doing…are you at that level?
Honestly sometimes you have to realize that parents are paying $$$ of money and want to make sure you have a realistic chance at a job when you are done…this is sort of the price you pay for getting your parents to pay for college. So you may want to look at colleges where non-majors can be involved in college plays and where they can take theater classes as electives.