What to do to help an age difference?

I am going to take a class (Biology) that I would usually take when I am one or two years older, but I am taking it now. I am going to be taking it with people who are all older than me. I know I am pretty gifted with this subject and I am worried people will think I'm trying to show off because I'm ahead of my level. Should I refrain from answering the teachers questions so the other students don't think I am a show off? What should I do to make it seem like there's no age gap and be able to interact with my peers? Thank you in advance.