I don't know what to do next?

Ok so I just found out I was pregnant a few weeks ago. I just turned 20 and just moved back in with my mom. I was afraid to tell her but I finally got the courage to tell her. When I told her she didn't believe me.  I took a test it was positive like I had already knew it would be. So she gave me a choice . Either I can move out or give the baby up for adoption. I'm not sure what to do. As much as I want this baby it's not in my budget and my boyfriend agrees. What should I do? 😥😭😰