Are the others right about my relationship...?

My boyfriend and I met 8 months ago at high school. He was 16 and I was 14 when we started going out. In December of 2010, he turned 17 and next month I'll be 15. We've been together for 8 months working on 9 and we've never broken up although we do have intense heated moments. He's a sweet boy but when I took him to meet my mama the other day, he seemed shy and answered questions with short unintelligent answers and it really kind of embarrassed me. He did respect her by calling her "Ma'am" and saying please and thank you but she still seemed not to like him. Then last night she told me that I seemed to be the smart one in the relationship because my boyfriend doesn't know what he's doing or what he's going to do in life. She said nobody thinks highly of this relationship because people are worried about your future and your boyfriend is just a weight bringing you down. My grades have been good and everything has been going well yet, she still called me weak. Yet, my father, he doesn't complain much about my boyfriend. As long as my boyfriend respects me and my priorities, my father says he's a cool dude. But my mama doesn't support this relationship at all, telling me that I'm just going through a phase with him. Is she right or should I hang on to a relationship that's not even harming anyone?