Guys I need help?

I'm having really bad problems with confidence.

I think I have weight problem such as I'm 5;4 and weight 128 pounds it goes up and then I stop eating and it goes down to 128 or 129. I want to balance this weight and maybe lose weight down too 110 could I get some help. It's hard for me cause my family eats pretty bad an my mom won't let me go on her diet. I play sports and work out and still nothing is working for me. Help plz.

Oh yes and my cousin who is 5;4 and weights the same as me but is 14 turning 15 soon wants too know if that's fat or not.
Guys I need help?
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