When is the best time to get our working cocker spayed?

[FreshLeticia]

Blodyn is 9 months old and started her first heat yesterday. All fine. She is a pedigree working dog as well as our pet and will be working with my DH. What is the best age for spaying?
I have read that non-spayed cockers are prone to breast tissue cancer, but am also concerned that as they are a later-maturing dog, we don't want to affect her development.
She is pretty busy as it is, I would really like her to mature properly.
Help??

With a working dog, I go for about 18 months/2years old because I want them to mature - hormonally and physically. I work labs though and they tend to mature more slowly than working cockers, so you may want to adjust that to fit. Mine often have two seasons before spaying if I'm not going to breed from them.

thanks, that's what I was thinking really. I do want her to mature properly and the working cocker guides do all say that they are late maturers - sounds like not as late as a lab though!
DH also wants to make sure she is physically strong enough to hunt with him and mature enough to do as she is told - although she is doing well so far. She is acting a bit teenaged today, silly and messing around. Hormones eh.