Young adult. At 12 I was making decisions most adults these days aren't capable of. Maturity comes in all ages. It depends on your up bringing as well. There are some 12 year olds I would trust before some 40 year olds I know.
No not until I was 5 lol but from about 13 on I kind of raised myself. My dad was a bad alcoholic and my mom was submissive. I was the youngest of 3 kids so when my sisters moved out at 18 (they are twins) I had to fend for myself. I grew up quick. Made me stronger though :-) on a good note my parents are doing well now. My dad tries to make up for failed parenting by being super grandpa. LOL