Yes, she is a little overweight. Ideally she should be 20kgs. But need not worry. This can be treated with simple life styke modifications, but u should implement very strictly for 4-6mo.
1.dont let her eat chips, puffs etc and fast foods.
2.make her play outdoors for 1-2hrs daily.
3.Dont add any boost etc in milk.
4.give her lits of fruits
5. No chocolates, ice creams etc.
6.please get one
thyroid test done