Most 8 to 10 year olds may only pull to 21" or 22" so at 25 lb @ 28" may be light enough to handle. I have found most are more comfortable with a 20# # 28"
I really helps to had some bows to try on. I keep a whole box of fibeglass bows of various length and draw for 'test' bows. Then they can get an idea what they might like in a longbow or recurve. I also use those fiberglass bows in the flu flu 'arction archery' course that I put on for Cub Scouts and youth groups.
A lot of kids learned on a cheap fiberglass and cheap arrows, but the better the gear the better the shooter will become.