losing my virginity- advice?

I'm super nervous. Been told to talk to him about it, he's not a virgin and I don't wanna look too nervous. Should I just lay down and let him do everything or do I need to stimulate him? Do we need foreplay because I think I'd feel awkward with his head between my legs or me touching him. Sorry TMI but I only masturbated by touching my clitoris and when I tried a finger (and I'm pretty skinny and my fingers are super small) it was so tight. I don't want him like not to fit in and feel even more awkward. Please tell me everything I'm okay with super long answers😅
Btw we're currently in Germany, I'm almost 18 he's 20 and it's totally legal here to have sex with people who are 21+ and once you're 16. (creepy I know) 
Also we've been together for one and a half years and I know he's pretty fustrated now because he had no sex since we're together. 
He's veeeery respectful always asks before touching me anywhere near my private area. He doesnt rush anything he's very gentle but I feel ready and I want it but I don't know how.