Im confused what to take for my AS Level (A Level) ?

Hello! I have completed my O Levels with Biology,Human Biology,Physics,Chemistry,Mathematics-B and English..the grades were pretty much good...now i have been admitted to college where im supposed to pick my subjects for A Level..well i have an ambition of being a Doctor because im very good at Biology and Chemistry..if not then i might want to be a Barrister...So for A Levels I *temporarily* chose Physics,Chemistry,Biology and Law but i didn't choose math because i dislike math...so was that a right choice? Please let me know if A Level Law is easy or not???