Hi and welcome. Kudos to you for rescuing a dog, and I think getting an older dog was a wise choice, given that your kids are young. Puppy plus young kids can be really difficult. This dog might have some issues, but her maturity means you don't also have to deal with exuberant energy or housetraining.
Crate training can happen at any age, and is a great management tool. In the meantime, you can confine her to a room where she can do minimal damage using a baby gate. Kitchen or bathroom can be a good choice. You could also get her an ex-pen, another great management tool. https://www.aspca.org/pet-care/virtu...crate-training
You don't say if this dog has been around babies before; if not, you will need to make sure she's not upset by the different stages your son will go through. Some dogs are fine with babies and older kids, but not toddlers, or love toddlers but not babies. Some dogs also seem to love anything human. Until you are certain of her feelings toward babies, I'd strongly recommend keeping her and the baby separated. I'm not convinced tying a new (to you) dog in the car, then adding a baby and a child is a great idea unless your car has a place where the dog can ride, completely separated from the kids. I'm not trying to be an alarmist, but until you know this dog it's better to be safe than sorry.
You'll need to teach her some impulse control at the door, so she's not always trying to escape. https://www.aspca.org/pet-care/virtu...and-games-dogs Teach Your Dog to Wait at the Door
It'll take the dog a few weeks to settle into her new home, too, so you may need extra patience at first while you get to know her and she gets to know her new home and new people.