Does anyone know spells to become a girl?

I am very sorry, but magic doesn't really work that way.

Much as a "magic spell" would solve some of the initial problems of someone wishing to become a girl, it would ultimately cause as many or more new problems.

Gender issues have been part of humankind's history since long before we started writing that history down.

I suggest you seek the help, advice, and council of your family physician, a counselor, or other person you can truly and honestly talk with and who's advice you respect.