Aitah for getting an abortion without telling my mom?

I feel bad because my mom has had trouble having kids. Me and my little sister are her miracle kids. She's had 4 miscarriages/ stillbirths.

But I'm 15... I had sex for the first time and got pregnant. I was freaking out, my bf lied and said he was wearing a condom but took it off while we were doing other stuff. I told my step mom and she asked if I wanted it or if I wanted to have it and give it up or abort and I said I didn't want to go through a pregnancy yet so she took me to a clinic and got me pills. She took care of me and helped me through everything.

I'm scared to tell my mom and I broke up with my boyfriend before I found out I was pregnant so he doesn't know either.

Aitah for getting one? It was the best decision for me but I feel bad only telling my step mom and my dad.