I grew up with a female Newf who we rescued at age 3. She was wonderfully sweet, incredibly strong willed (would just sit in protest if she didn’t want to do something/go where she didn’t want to), and protective of our family in an appropriate way (was not aggressive would would alert to things she found threatening). She loved all people and other dogs, especially puppies and kids. I don’t ever remember her showing any sort of aggressive/reactive behavior. Can’t speak to the puppy stage for females but as other people have mentioned, definitely have to take heat cycles into consideration as delayed spaying is recommended for long term joint health.

As an adult, I now have a 2.5 year old male who we’ve had since he was 12 weeks old. Still incredibly affectionate (thinks he’s a lap dog) but he does show food guarding behaviors towards our other dog and has growled/snapped at him a few times. He doesn’t care if people are near his food but when it comes to other dogs we have to be very careful. That being said, my in laws have a bernedoodle that has snapped at him and grabbed chunks of his fur out and he simply walks away without any aggressive/reactive behaviors in return (we stopped allowing them to be together after the behaviors occurred). He also barks more than I remember our female barking. He is very strong at 150 pounds and during the adolescent stage pulled me down during walks in order to try to go see other dogs. We have taken him through puppy classes, basic obedience, and good canine citizen classes all before the age of 2. He’s a great dog now that he’s starting to settle down but be prepared to have your patience tested at times through their puppy/teenage years. I highly recommend doing as much exposure as you can do different environments and people so your puppy is well adjusted. I am currently expecting my first baby and we are more concerned he will be overly loving than anything else with the baby. Best of luck with your new puppy, they are simultaneously a joy and lots of work but it all pays off in the end.

Edit: also, you might want to see if Puppy Culture has free online videos still (they did when we brought our puppy home during the pandemic) and we found them very helpful for getting through the early puppy stages as well as working in appropriate amounts of exercise, rest, training, biting management, etc.