Just thank God that it's a son and not a daughter starting middle school! Girls are MEAN at that age.
My advice to your son is to get involved and "To thine ownself be true.".
We got lucky, my daughter is starting her last year of middle school and she has had a wonderful time.
I was so worried about her starting, going from 70 kids in her elementary 5th grade to 300 in the town middle school, but she came out the first day of 6th grade, beaming, saying I LOVE it!! And it's been smooth sailing socially and educationally, just an all around good experience.
I've never had issues with girls being vicious and mean, not myself, and not with her..not yet anyway. Fingers crossed!
Classes were tough, which was good, she finally had to work a little bit. She made the softball team both years, joined a service organization club, joined League of Representatives, made NJHS, is very busy with band which is huuuuuuuge in our town. Over 2/3 of the students are involved in band or choir, jocks, popular kids, nerds, everyone.
I agree with the advice given, keep your options open, be yourself.
She is not part of the most popular crowd, but she has good friends, her core group and then various others from other groups, no need to limit yourself.
She is extremely organized, and that came in handy in ms. Work hard, don't fall behind, stay on top of things with all the different teachers you have, that's important.
My kids also play town baseball and softball, football and cheering plus went to the town summer rec program and that was a big big plus, IMO, because they knew kids from the other elementary schools in town that fed into the MS.
She and her BFF from 1st grade are still BFFs even though they never had a class together during all 3 years of MS.
They've both made new friends, drifted away from some elementary school friends, but all naturally, no drama.
If there are crappy obnoxious kids, the grade is big enough to avoid them. But it's also not so big that they get lost in the shuffle.
All that said, my son starts 6th in September and I'm a wreck all over again. I'm hoping its as good experience for him as it has been for my daughter so far. Nervous!