For a male single skater (it's different for pair skaters and dancers), 24 would be realistic, 28 hardly unless he's an absolute genius and a late bloomer.
The ideal height would be somewhere upto 5'7'', 5'8'' is also still possible, but above that, height can get in the way. There are single skaters that are 5'9'' and every once in a while you see someone get 6 ft, but up to 5'7/8'' is ideal for the technical elements.
Eating disorders are common, but it's not like all of them have one. But if the character has one, it won't be surprising.
They can go to high school, but often tutors are involved.
I would recommend you check out this link: International Skating Union - if you scroll down, you can select skater biographies for the 4 different disciplines, which should give you an idea about typical age ranges, heights (in cm, but you can convert those), and such things. They also have average numbers of training hours during the on vs. off season. I would check out the Americans, Canadians, Russians, and Japanese, plus S. Lambiel (Switzerland) and B. Joubert (France), they're good examples.
Weight-wise...well, I htink there's a reason why weights are not posted in the official bios. I've heard 120 lbs about a skater who was 5'8''at the time and that sounded realistic for him. Some are a little heavier.
There's two types of male skaters - those that dothe technical stuff via muscle mass (get rotation etc), and those that are particularly light and get in the air easily without much muscle mass. Compare Brian Joubert (FRA) and Johnny Weir (USA), for example on youtube. Two entirely different skating styles (most skaters are somewherein the middle but they're nice extremes).