Puppy/adult dog play

I have an 11 week old pit/lab mix male. And a 3 year old pit/lab mix female. I wish I could post videos here because I’m constantly stressed if the “playing” they’re doing is appropriate. Older dog has always been chill and quiet, even as a puppy. But my little dude is constantly growling when they play. We’ve had him since he was 6 weeks old (got him from the shelter) and he’s always been like this. We monitor them every second they are together. But it’s been 5 weeks and he still growls and bites my older girl constantly. Both tails wag while they play and it seems like they’re having a good time, I just don’t know if I’m encouraging the growling and biting by letting them “figure it out” for a few minutes. (He’s also on a strict crate nap schedule so it’s not because he’s overstimulated, it’s just how he plays). I guess I’m just looking for validation that he’s not going to grow up to be an aggressive/reactive dog