Depends on Height. Height and weight go hand in hand. An average weight for a 5 foot girl is totally different than for a prebubertal 4 foot 5 inch child. Check with your doctor, and compare not age but weight for height.
Between 90-100 lbs. A 13 year girl who is 5'1" is around the 40th percentile for height. At this age somewhere between 90 and 100 lbs would put her around the 40-50 percentile for weight. The cdc and who have growth charts that can be helpful. Http://medcalc. Com/growth/ also ask your pediatrician to see your daughters growth chart at the next visit.
No ideal. She might be 90-125lbs and be healthy. If she's much more than 125, her bmi (body mass index) is getting into the over weight range, which isn't healthy. "ideal" is strictly one person's opinion, and what's "ideal" for one isn't "ideal" for another.