1) Take up a sport other than wrestling. Many WWE wrestlers started as well-rounded athletes playing football or other sports. A lot of schools don't allow girls on teams like football, but it's illegal for them to do so. You don't need to be a world-class athlete, but you should be conditioned as a wrestling match is a strenuous activity.
2) Take up amateur wrestling in school. Having a background in actual competitive wrestling has never been required, but it will help. Fans are growing more and more to like wrestlers that can pull off actual wrestling moves.
3) Attend professional wresting schools. The WWE does not personally sponsor any schools, but there are many independent schools and some sponsored by smaller wrestling companies. Check online to find a school near your area.
4) Take acting or speech classes. Remember that WWE wresting is a mix of sports and theater. You need to be an entertaining character as well as an athlete.