Chuck offers a lot of great advice here. As a freshman in HS, I was in a similar situation as you. By the end of the year, the only upper classman who I didn't sit above in chair placement was my older sister, who was a senior at the time.
This is going to be one of those situations where you'll just have to be you, but remember that to get respect, you have to give it first. Just do your best, play as good as you can, and continue to strive for improvement.