When females reach 110 lbs puberty kicks in. My niece was kept on a strict diet during her swim team years so she didn't start her periods until she was 17...her body fat % had been so low it retarded development. Think of all those Olympic gymnasts.
Your daughter may be being teased because of her size and weight.You need to make her teacher aware of your concerns so that she can start taking note of what is going on and why. If this is the case, it is the teacher's responsibility to STOP the other students from picking on her.
In the mean time, see a doctor about her weight. Have her referred to a neurologist to have her tested. ONLY a neurologist can diagnose ADHD NOT her teacher!
Also, check into seeing a counselor or psychologist at school or better yet on your own.
I raised an ADHD son and an ADD son. It runs in our family.
Take care of everything NOW so she can start off fresh and ready in September.
D. D.
Teacher 15 years and soon to be a Principal
P.S. The is no such thing as BIG Bones. Having been in the Science field for 15 years and two years of nursing school, I can assure you bones, unless one has the disease John Merrick had (Elephant Man), all bones are the relatively the same diameter in relation to height and age as the next person. Saying someone is "big boned" is just a P.C. way of saying overweight.