Leaving all girls school

I go to a highly ranked all girls grammar school, and i’m in year 9, so it’s harder for me to leave, but my school is destroying my mental health, and i just feel so lonely, i also kinda want a boyfriend, and just to be able to socialise with anyone, regardless of gender. The school i go to is quite clique-y, and i have no friends there, it’s also small and run-down. How do i convince my parents to let me move schools?

Is there a mixed Grammar nearby? If so, show that it gives more opportunities. Idealy move before options are chosen - there may ne a wider/different choice at a mixed school.

i live in reading, and the nearest mixed grammar school is in slough