() writes:

i have a female siamese (pedigreed) that is 6 months old. Is there an
optimal window for having her spayed? Do I need to worry about getting
her spayed before full sexual maturity? With boys, it's best to have them
neutered at about 4 months so that they don't develop tom characteristics.

I'd do it ASAP since she is getting to be old enough that she will be
going into heat soon if you don't (and there is no reason to let that
happen). Talk to the vet who will be doing the surgery if you have
any questions about it.

-Sandra