Breast Reduction

I’m 18 years old and I wanna get a breast reduction. My boyfriend of 2 years thinks I shouldn’t change myself. I asked if he would break up with me over it and he said he doesn’t know. I’ve mentioned getting it for a while now and he always says no I shouldn’t do it. Everyone else I talk to says I should do what makes me happy. I’m so conflicted on what I should do. Any advice?