I am 13 and i am 5'4'' and my BMI is 23.5 is that bad?

This summer i want a swim suit body or a body that i am well embarr to be in...well i have a bit of a tummy and well i also would like to know if you have any good well ideas for a diet that would get rid of my tummy plz help will rate up on best answer...thank you Candy_starr