Become a singer? A member in a girlband?

First of all, I have always had a pion for singing. I started at age 8. I am now 15. Singing is my way to express myself and to relieve myself. People have told me I have a lovely singing voice but I dont really listen to them. I love singing so much that I started taking singing lessons and the vocal coach I have good "afinacion"- yes, a word in Spanish. Don't know to say it in English. My plans are to become a doctor in medicine but singing has been really interesting me. I wouldn't like to go solo..I'd like to be in a group.Westlife are my inspiration! <3 The thing is, my parents don't want me to be a singer. Im only 15 and they basically control my life. Any advise? Should I just give up and become a doctor?