Telling my mom

I’m a college senior almost in my third trimester. I still haven’t told my mom but I already know how she feels about pregnancy. Both of my older sisters have children & I know she sees it as a disappointment, but that’s because they are so dependent upon her (not working, not in school, etc) & she’s really judgmental. I doubt that she will be very happy and will probably feel like I let her down, especially because I am her youngest child. She’s always seen me as the “smarter” child with a great future, which I hate because she always has high expectations for me & not them.

Any advice? How did you tell your parents? how should I tell her? Should I just flat out say it or find an easier way to break the news? She still helps me financially but we live in different cities so I have to find time to meet with her. & my bf is very impatient & wants me to do it soon.