I'm 17 he's 20 years old is it okay?

so my boyfriend is 20 years old and I've recently turned 17 years old last month.he's about to be 21 years old is it okay for me and him to be in a relationship,i'm a really mature person and know how to protect myself we've had sex just one time and we definitely used protection.My parents don't know i'm dating him because they'd never accept him as my boyfriend because he's older than me and i'm still a minor.