When should i tell my mom im pregnant ??

Where I live I can get prenatal appointments without a parent , I'm 16 but can't bring myself to abortion . But , when should I tell my mom that I haven't been partying , but was actually at doctors appointments .

My life is a little messed up , I live in the projects . Please don't judge . I'm scared.

The father is supportive though(he's 26)😛 .