We had MuttDog spayed at approx 6 months - couldn't be more definate as she was a rescue/dumped.
Spoke to the vet and advised her that Mutt was going to be around 'complete' dogs every day, she was quite happy to spay from 5 months onwards, as long as I understood that there is a slight possibility of incontinence problems later in life the earlier bitches are spayed. It was a negligible risk, so I went for it.
Another bonus for me was that if you don't let a bitch have a season she doesn't get the 'rush' of hormones from puberty, so is likely to be calmer in general (but no-one told MuttDog that, and she's still a loon )
Hi there when my dobe bitch is in season she sulks! Sleeps most of the time and just wants to keep her self to herself, bit like us really! But stick to advice about walking and the garden! Male dogs are very determined and also a bitch can turn very nasty and cause injury to another dog because they don't want mounting. But to be fair you and your girl will breeze threw it, just use common sence