Should I tell my mother that I lost my virginity?

Well, some weeks ago I lost my virginity with my boyfriend. My mother knows about our relationship, but I'm afraid to tell her about my virginity.

My sister is 31 but she was 17 when she got pregnant and that completely changed and destroyed the course of her life. This was a difficult problem my mother and her had to handle.

I'm 16 now. And I believe that telling this to my mother would make her overly concerned and even obcessed.

In the other side, I wanted to go on a medical appointment for birth control so I can start taking the pill. That would make me and my boyfriend much more comfortable in our sex life even because we had a few scares with contraception. The problem is that I can't make the appointment by myself, and this part would be easier with my mother by my side.

I'm just scarred about how traumatized she was with my sister's pregnancy.