Girlfriend now says she wants to wait until marriage for sex? Said we would talk about it tommorow which is today?

Long story short me and this girl really like eachother. We were about to have sex and almost got caught in the car as i was trying to put it in and felt like we should stop because its uncomfortable and hot and didnt want to get caught. We are both virgins and talk about sex all the time. We were really passionate in the car making out after and telling how much we like eachother. Then the next day she said she couldnt sleep all night and i asked her why and she said because she couldnt stop thinking about how much she liked me. And i said i like you too but its that shouldnt keep you from sleeping. Then i found out it was because we almost had sex and that she feels guilty because she made a promise to her mom that she would wait until marriage. Shes told me before that she used to want to wait but now doesnt because of me. But once we actually almost try it at the worst place in a car, she thinks shes made up her mind and doesnt actually want to do it anymore after all. I told her that thats not what she really wants and that she letting what her mom think of her control what she actually wants. I mean were both virgins and really like eachother and would talk about sex all the time, we even had cam sex on facetime.. Shes the only girl i want but thinking about waiting til marriage to have sex is crazy especially after we almost did it and she passionately said she wants to have sex with me so bad. Please help me, we both had an argument and cried on facetime