This place has different names (you should ask according to your girlfriend's local address), some are called "Auntie" (it feels a little old), some are called "Auntie", some are called "Auntie", and some are called "Mom" directly after your girlfriend.
It's actually quite simple. If your partner lives in the countryside, you can call uncle or aunt, and the rest will be easy. It is impossible to call all relatives and friends when we meet for the first time. It's easy if you do it.
Auntie, auntie is a common saying. If she comes from a prominent family, you can call her Mrs. So-and-so.