Yes, they do lose their teeth. There were a few times when I was playing with Baby where a tooth just randomly fell out of her mouth. I would say teething starts around the 4 month mark. As for when it ends, it varies. Baby still didn't lose all her teeth by the time she was roughly seven months old, so the vet removed 4 of them along with her spay.
I agree with starting around 4 months. Angel stopped losing her teeth just recently at 6 months. She lost several at a time though so it doesn't always happen that fast. She was actually losing a tooth a day for awhile!
Oh yes, young puppies... well puppies in general actually... love to bite while playing or just exploring. It is just their way of learning their way around in a sense. It is how they learn what things are. She will learn soon enough that people are not chew toys.