I feel bad for lying 🤥

So my mom is religious like no sex before marriage. When I was 17 I lost my virginity to my ex the reason how she found out was because I thought I was pregnant. Fast forward to now I’m 23 and I am having sex with my now boyfriend. But when my boyfriend are going on dates she texts me “no sex.” Because she doesn’t want me having sex. So since we are having sex she asked me are we having sex and I lied and said no. She doesn’t know if we are having sex. I hate I lied but I felt like I had to because last time she kept me away from my ex for a month.