Is it possible to go to an acting school AFTER college?

I am currently a student at Dartmouth College, however I have a low gpa due to failing science courses for pre med school: it's 3.0. I still want to be a doctor, so am taking another year to do the prereqs and get my gpa up, however i already have the courses for my psych and english major and am thinking of finishing up to get my theater minor as well. I enjoy writing, acting, singing, etc, but that won't pay the bills. I've always had a dream of acting on stage or for TV, but it was stifled by parents. the question is if I take the year to not only to my pre med reqs, but to finish my theater minor and participate in more productions (i have acted in two and have written plays for 4). Should I go to an acting college during my gap year of applying to med school? Can I even get in and how? How hard is it to get into the Yale School of Drama? PLEASE HELP i'm sooo confused. I will have a BA, but do I need to get the BFA if I want to continue acting?