When is really the RIGHT time to start potty training?

My daughter just turned 2 she always takes off her diaper and now it’s been more. There’s times she has had accidents on both parts. I put her on her potty training and sometimes she will stay others she won’t. She doesn’t know yet how to ask to go to the bathroom she doesn’t pull her undies down yet. So idk what else to do? Or wait til she understands? How does it work in the nights though? Do you have them wear pull ups? Or leave them in they’re underwear?

Help 😩🤯 FTM