Telling parents

This isn’t a planned pregnancy and my parents don’t like my partner. I had been pregnant last year in September and decided to terminate the pregnancy which I don’t actually regret but I don’t think I could go thru again, so I’m planning on keeping this one. Currently living with my parents so I can save up for my own place. I am the oldest, and idk how to tell my mom. Debating going with a shirt and an ultrasound, but keeping it a secret for as long as I can..any advice would be appreciated.