Is my weight normal fo my age?

I am concerned because I dont like what I see everyday. I am 15 years old I am 5"2 and a half, and I am 128.3 pounds, I have wiggle thighs and my belly kinda...sorta has chub to it. I want to look good this bathing suit season, I am not saying I wanna be like 92 pounds, thats just to tiny, I just wanna firm up my abbs and have a nice bod, and maybe get down to the weight of 120. Can anyone help me?