I'm so glad everything has worked out so well. Well, I remember when I had a Boston who came into heat a couple of times. At first it was just dripping blood spots then when it was pale in color, her vulva was swollen. That's the time they are ready for breeding. I had her bred with a little CH. and I'll NEVER go thru breeding another dog again.
I'd advise a diaper inside, and if she isn't pad trained, I'd put a harness and leash on her to take her out potty. You just never know what can be lurking about and you don't want her hurt.