Hi Ania!
All I can do is tell you how it went for me. Of course, I have no way of knowing if my experience is relevant to your kids' situations.
I was a shy, quiet kid. I was bullied in gradeschool. When we moved I started 6th grade at a new school and found it difficult to make friends. I wasn't bullied but I was just sort of ignored. My mom had me take a test to get into a local school for the gifted and I passed. I skipped 7th grade and started 8th grade at the gifted school. I loved it there and enjoyed myself until we moved to another state the summer before my junior year.
My junior year I started at a regular high school at the age of 15. I actually suffered more mistreatment from some of the teachers than from the other kids. I took Calculus as a junior and it was very easy for me. The teacher didn't like it that I came from another school and was better than "his" students. He constantly singled me out as in "Didn't anyone get this problem on the homework? I'm sure Cathy got it right--Cathy come up here and show how you did it." This happened every single day! He even went so far as to put a very long arithmetic problem (no calculator allowed) on the final and then announced to the class that they shouldn't worry about that problem, he only put it on there so I wouldn't get 100% again. He always announced how I had "ruined" the curve after every exam. I complained to the school counselor about this teacher's treatment of me. His response was, "Well, you're getting an 'A' aren't you? What are you complaining about?"
Mostly, I was just ignored by the kids. I didn't really make friends there and didn't have any interest in attending prom, etc. Since I was shy and reserved this didn't really bother me, I was just eager to go on to college which I really enjoyed. I did join the swim team in high school and lettered in swimming. I tried out for softball, but since I was a junior I had to try out for the varsity team which I didn't make.
All in all, I am glad that I was grade skipped--it allowed me to go to college as soon as possible. The high school social scene just wasn't that important to me.
Cathy