I don’t know how to tell my mom I’m pregnant

So on Thanksgiving I found out that I’m pregnant💕 best news I’ve ever received, especially because my boyfriend and I have been trying for almost a year. His reaction was exactly what I thought it would be 🥰 but the problem is.. my mom doesn’t like him.. she also expressed how disappointed she’d be if I were to ever get pregnant by him and that if I did, I should get an abortion (abortion isn’t even an option btw). It’s been so hard keeping this from my mom because we tell each other everything. So how should I go about this? I was thinking I should wait until my first ultrasound so she could actually see that her grandchild is in here and won’t be so mad. HELP!