Nervous to lose virginity

M22, still a virgin. I’ve had a few times in the past that I could of had sex but didn’t. There’s this girl that wants to have sex but the only place we can have sex is in a car since we both live with our parents. I’m nervous I won’t be able to get hard if she tries to give me a blowjob in the car. I know I can get hard around her because she has made me before when she sits on my lap and we make out but the thought of us just being in the car and whipping it out idk I feel nervous I won’t get hard. Not long ago she asked as a joke but serious if I wanted road head and that’s what made me think about this. (Felt it would be hard to get hard if she just started right then and there) I probably would get hard after a minute but I’m a “grower not a shower” so nervous for her to take my pants off and I’m not hard yet and she feels some type of way about the size. Also she has been with many guys and is younger than me so I feel more nervous because I’m a virgin and she doesn’t know that. Im sure it’s all in my head, any advice appreciated.