Well, I originally wanted to wait until I was done with my first trimester to tell my family. My mom actually guessed it on Christmas eve. I was so upset that she guessed my secret that I ran off and cried. She was actually very gentle about the whole thing. I thought she would be really mad and yelling but she just calmly and rationally told me that she thought I was making a mistake (too young, poor, in my first year of college). It was an upsetting night for sure, but the next morning she woke me up by apologizing for some of the things she had said (bringing up termination and whatnot), and told me she would support me no matter what. I was 11 weeks then, and by the time I was 16 weeks she was really excited to be a grandma. She tells everyone and is so excited to find out the gender on March 1st. It was a relief to have her know my secret, but I still got nervous and shaky when I had to tell my dad. I was so surprised his reaction was super calm too. My parents are divorced for 17 years now, yet they still remind me of each other a lot. I cried telling my grandma, because I thought she would be really disappointed, but she just told me that I would make a great mother. MY heart was beating so fast when she told me that, it was the first time anyone had said that and it made me feel so amazing. By the time I told my other family members, it was a walk in the park.
I think the hard part is getting comfortable with the idea yourself. Once you tell a few people, it gets wayy easier to tell other family members. I'd tell whoever you are closest to first, even if its an aunt or a cousin rather than your parents. I would have told my mom first even if she didn't find out. My advice is just to blurt it out after having a good day together, definitely dont break the news after a negative day.
good luck to you!! i know exactly how you feel! telling family was the hardest part for me. but now everyone knows and they are starting to help me get things for the baby and save up for my own education to continue. i hope it goes well!!!