I don’t know what to do!!!

So I’m only 14 and a virgin. I’ve always judged girls who have sex this early in life. Buttttttt this guy and I have been on and off for a year now. We just started talking again and I want so much to have sex with him. My mom always told me to tell her when I’m ready for sex so that was she can get me on birth control. I’m so scared to tell my mom that I want to have sex. I feel like she’s gonna be disappointed in me cause I’m her little girl and I’ve always talked about not wanting to have sex.