Mom is going to take me to the doctor for a virginity test

Guys I'm so nervous and scared. I'm 17 years old and I've been dating my boyfriend for 2 years but we recently started having sex. My mom overheard me masturbating and I was lightly saying my boyfriend's name. She barged in and started yelling, asking me if I've been doing it and that my "little friends" probably encouraged me to. So I told her no I'm not having sex I was just exploring myself and she was like well thats great but now a doctor is going to tell me whether or not you've been having sex and if you are you are so grounded. So now I'm freaking out because when I turned 16 last year, my mom told me that if I stayed a virgin until 18 then she would pay for my apartment for one year and buy me a better car. I feel bad for betraying her but I love the hell out of my boyfriend and I'm the one who initiated it, not him. I'm just so nervous and I'm absolutely worried right now