Please. Help.

I am 23 with a great bf who is 25 and we have been dating for 1 year already. My parents really like him. We have even told them that we want to get married. The thing is that I am still living under my parents roof. Sex before marriage is a no no. Especially having a baby before marriage is a big no!!! I am 6 months pregnant and still haven't told my parents. I'm scared. And my boyfriend has been so kind that has been patient but last night he got really fed up with my promising that I'm gonna tell my parents but have not told them. He said that I need to grow up and tell them. Help. What happened to some of yall when yall told yalls parents? Btw my dad is strict. So now a week has passed by and me and be are in good terms. He is excited. We want to get married. But I'm scared to tell parents.