You have to do what you believe is right for you.
When you start high school you believe that you and your friends from primary school will be together forever. The truth is you will meet lots of new friends who will mean equally as much to you and who you might find you have more in common with.
Wherever you choose it won't mark the end of friendships but the start of a wider circle of friends.
I have had the same discussion with my own daughter.
As for the Girls school comment, maybe it's just jealousy because you have the choice and they don't..
Follow your heart and you won't go far wrong.
Let us know what you decide..