That’s pretty normal for any puppy, but they have to learn that it’s not ok. When it happens, let out a loud “OUCH!” or something like that. The trick is to startle your dog with your voice, and then pull away and stop playing with your puppy for a while. Your pup will soon learn that when he starts to bite, his playmate (you) goes away. It’s important to be consistent, and teach the whole family to do the same.
Another way is to redirect them to chew on a toy, but I’ve always had success with the ouch method. I hope it helps.