I've sent dd to a girls school as I personally think girls do better at them and I really want her to get on well with girls - she only has an older brother, as I did, and I think she needs a chance to be herself in her own environment.
I'm wondering if it's normal for mums to be a bit anti-boy at girls schools, however. Many of the pupils in dd's reception class are only children or have just sisters (I am sure if I had a one sex family, I would look more closely at mixed education). I've heard lots of comments about when boys come along to pick up or to parties - girls crying that they are being rough, noisy or chasing and the mums backing it up. One mum even saw the head recently to request boys stay in the cars at pick up time and not walk into school I've seen the boys and girls racing about, but NEVER anyone get hurt.
Aibu to think about looking elsewhere for dd - there is a a school nearby which is more closely aligned with the boys school I think, at least in terms of practicalities and dates etc? She's just started reception. But has done nearly 2 years in the preschool bit.