Do I have a say in this?

I've been looking for a dress for my 8th grade dance, it's not for a while, but I've been trying on old dresses from my ants and grandmas, there was only one that I really liked, but it was a bit to small :( so I just tried on my aunts wedding dress, yes wedding dress. It fits me very well, but I hate it. It can be made into a dancing dress, but i really don't like it. Now don't get me wrong, I'm not one of thous girls who fallow the crowed so I'm planing on wherein a dress the is really really different. Butt I really do t like this dress but my mom is already planning a fittingfor me, and it makes me feel bad because they really want me to where it, I dont have th guts to tell them I don't like it... I don't know what to do...