My mum wants me to go to a sixth form/school that I don't want to go to?

I know people always say "You're mum knows best" but I know that going to the sixth form she wants is not going to make me happy. She chose what secondary school I went to, and all my friends went to the secondary school that I wanted to go to. I've spent 5 years in this school, and I don't like it, I only have like one or two proper friends there that I see outside of school. So I won't really miss them that much. So that's why I want to change school for sixth form, but she is saying "No, you're not going there, that's for underachievers, why would you go to a great school just to take a step down at A-Levels". And to be honest I know that going to my current school's sixth form will probably get me better grades, but I won't be happy. Not to mention my school is an all boys school, and so is the sixth form. I want to go where it's mixed, ill get pretty good grades, and ill actually have fun.

So anyways, I have my mind set on going to the sixth form that I want to go to, can she stop me from going there? Surely it's my choice where I want to study for my future? It's closer to my house than the one she wants me to go to, it's also non school uniform, so she doesnt have to pay for any uniform stuff.

So you are telling him to have fun in uni which is more important than college even though people who "have fun fail"

You sound very contradictory...