I agree with your decision to lose your virginity. It's a wise and sensible decision you've made.
Putting myself in your boyfriend's shoes: I'd know you're a virgin. I'd fully understand any lies that you said about this, as they made sense from your point of view at the time.
For the grand evening, I'd be looking to put aside the whole evening. Somewhere quiet, private and comfortable. And to be in no hurry. I'd look to give you more than 1 orgasm before my penis came anywhere near you. Although that might get modified down to 1 depending on you.
It's possible that as things warmed up it would become apparent that the 2 of us weren't sexually compatible, in which case - depending - that may well result in an abrupt end to proceedings. Which is fine - as the sex should never be seen as foregone conclusion.
My overall attitude would be that your needs, desires, feelings would be placed as more important than my own.
For the pain or discomfort it would be a case of going ahead, only if at the time you were 10,000% sure that it was worth it and it's what you wanted.
From your point of view, go ahead and enjoy this wonderful, magical, memorable evening. You should feel comfortable discussing any subject with your boyfriend. And you should dictate the pace and the nature of proceedings. Don't be a passive sack of potatoes. And don't feel inferior to him because it's your first time.
If I were in your shoes I'd make a secret audio or video recording. As protection against the 1 in 100 chance that you get sexually assaulted or raped. And I'd delete the recording without playing it back when things went well.
And I'd make sure the contraception was water-tight.