My PG son skipped two grades and was also on the small side. He periodically became anxious about his size and needed his doctor to reassure him that his height was within the normal range from time to time. That seemed to calm his anxiety for a year or two. He hit a growth spurt in high school although he is, even now, not what anyone would call tall.
More importantly, in HS he finally had a group of students he became friends with, spent the day with in advanced classes and who respected and honored his abilities.
We also dealt with rivalry with the older sister who was never GT identified although she has come to realize she has amazing strengths he doesn't have. She's the one who elbows her brothers aside to fix a sink or build a fence.
Being in different middle and high schools was helpful for her because she was able to be known on her own merits and not as his sister. She became more assertive and outspoken which for her was a good thing. It also helped him develop the independence necessary to go far away for career opportunities at 15-16.
