going from an all girls to a mixed

so i go to an all girls rn and the sixthform i REALLY REALLY wanna go to is mixed. idk if i want to do that js bc the last time i was in a mixed was primary school and i feel so comfortable around girls. i wouldnt really talk to the boys (for religious reasons im not meant to freemix), if i dont end up going to that one which i really want to as it would help me get into the uni i want to get into, then id go to the sixth form at my school which wouldnt mind but yh, help pls.