Talk with your vet on the procedure, and aftercare. They should send home a page or two of instructions. Watch the incision site for inflammation.
Most females have a smooth recovery, and keeping her lowkey for a couple days afterwards except for potty breaks and some leashed walks will help so she isn't jumping or stretching her abdomen.
As far as her age goes, many opinions on this, so I won't share mine...you do what you think is best after researching the pro's and con's of early spay.
I would think you can take her to obedience class if it is a few days after the spay, as long as no complications happen.
Her personality shouldn't change, hopefully she'll get tender loving care while at the vet.
After Onyx was spayed @ 6 mos she became a bit reactive when going to the vet and was reactive to females(techs and vet all female).
Not sure what happened to her, could have been just her waking from sedation and freaking out in a cold cage in a strange,sterile environment-so was imprinted(she has not
got steady nerves) A dog with solid nerves should recover from this fine.
Your pups hormones may play into personality afterwards, but most don't show any difference after being spayed. When they go into heat, some tend to have a behavior change until they come out of it, so you just have to manage the dog either way!!
I wish her a smooth recovery and you and your wife to not worry while she is having this done