What do you mean by that?
Ask if you can be bumped up to the Grade above, to a more mature class.
If you're able to keep to the work, and the class is actually generally more mature, it should be a problem.
Although, I do have a friend who was put up a year himself, skipping the last year of Primary School and going straight to Secondary.
He's social with everyone in our year, but of course, jokes are still made about him being younger. You get used to it and will rise above it. Just don't let it be a problem.
Otherwise, make a formal complaint with your guardians. Maybe they can get you another teacher who can actually control their class?