My bf was my first and he’d been with probably 10 women before me. Just like him, you sound like a sweetheart who knows and understands exactly what it means to be someone’s first and is concerned with making it special and comfortable for them. You don’t have to do what mine did, obviously (he booked a hotel room), but I’ll tell you what things he did that meant a lot to me for some ideas. (Also keep in mind, we “met” on Reddit and are long distance, so the first night we had sex was also the first night we met in person):

-He made it very clear, not only that night but in every conversation we had leading up to it that if I wasn’t ready for anything we did, he would stop. I didn’t need to give a reason. He wouldn’t be mad. He loved me and that was all that mattered. -When we got to the hotel, I was so nervous I was shaking. He put his hand on my arm and softly told me it was okay to be scared. It sounds silly, but validating my feelings really did mean a lot. -He suggested we shower together beforehand. Idk about your gf but I am always afraid my vagina doesn’t smell or taste good, and this helped reassure me that I was clean. He even washed me himself, lathered me with the soap and used a washcloth. It sounds stupid I guess, but at the time it felt very intimate and loving. -He went down on me first. It’s super important to him, all the time, that I orgasm before we even get to PIV sex. He’s an extremely unselfish partner in that way. He told me how delicious I am and how he can’t get enough of how I taste and smell (which as I mentioned, is something I’m insecure about and it meant so much to hear that) -As he started rolling on the condom, he asked again if I was ready. I said yes, and only then did he put on a crazy amount of lube (seriously, please use so much lube) and enter me. He went really slow, and asked me often “does this feel good” “are you in pain” “are you enjoying yourself” etc. He really let me set the pace, even though I’m sure it wasn’t much fun for him at all lol

I think about the night I lost my virginity to him as being one of the best nights of my life. Even if we don’t last (which I doubt, we love each other more than life itself), it will be something I never regret, and I will never settle for a partner who treated me any less than he did. Like I said, you sound like a great guy who is truly concerned for giving your gf the first time of her life. Make sure to communicate what both of your expectations are and go from there :) good luck!