Submissive play or fear?

[Luna and Yen]

Hello!

My 19 week old puppy (Luna) loves going to the off-leash park and sniffing other doggos. However, she seems to be fearful when other dogs want to play. She crouches low, has her tail between her legs, and lays down. This happens with all dogs, bigger or smaller than her. She's always the chased one, as oppose to the chaser! Yesterday, a more dominant puppy started chasing her and biting her (playfully I think), and Luna rolled down onto the floor and squealed from the top of her lungs!  I don't think the other dog hurt her or anything, maybe playing too aggressively? This has happened a couple of times before... ended up shaking, wimping and curled up by my feet.

Is this normal for her age? I'm trying to help her grow into a confident dog.

[Helen & Kirby]

I found going to a puppy class is wonderful.   Find one that lets  puppies play for a few minutes, then you "catch" your puppy and the instructor goes over behaviors, and then you repeat.   It is nice to have supervised puppy play by a professional.