Desperate need of Help!!!

So a bit of backstory I am 23 almost 24 years old and I've just found out I'm pregnant. I already have 2 kids from a previous relationship (twins) that don't live with me. it was a mutual agreement with me and their father. I see them every week though so no issue. the issue i have is i don't know how my family will react with me being pregnant again. my mum has previously said that if I get pregnant again she will take me to the doctors to abort. both me and my fiance don't want that. I just started a new job and my SO doesn't work at the moment. he's really excited but I'm just scared. Really need help and advice. Edit: the reason it bothers me so much is my mum is my main support. she was when I was pregnant with my twins and I'm scared I'm going to lose her