What kind of condom do i buy?

Durex or Trojans, make sure they're lubed just in case.

Do you still pull out if you have a condom just to be safe or does it depend on the girl or what?

Don't have to, but it couldn't hurt.

How much do i shave/trim and what device do you use to do so and what do you do to make it not itch?

Honestly dude, just get a nice pair of brand new, clean nose hair trimmers. Be careful (obviously) and act like you're trimming a hedge (ha), a little at a time off the top (ha).

I get nervous (or at least i did last time with my ex when she was going to give me head) so should i try like "horny goat weed" or other types of pills to help it out(I was thinking yes because there will be drinks and other things that will influence how well i perform) or just trust that it'll be better?

Dude, you're a virgin, if anything the drinks will help with that. Let me reiterate, you're a virgin, you have enough self produced horny goat weed to last the night, trust me. ;)

Do i let her know that I'm a virgin or only tell her if she asks or it pops up in a conversation?

This is tricky, but I would say tell her. Don't, however, just state it ("Hey I'm a virgin"). Look, you don't want to just outright say it, but you can't not tell her. If you tell her and she laughs at you, sure that's embarrassing. But if you don't and she finds out because you came to early, well... That may be a situation that would a little harder to live down.

How do we go from partying to the bedroom casually, like what line would i use etc.?

Wait, are you for certain this happening, or are you just assuming that's what's gonna happen? 'Cause that changes everything. And... To be honest, she's more experienced. If you take charge of that situation, and then let her know you're a virgin, that may backfire on you. I would just be affectionate, keep it light and let her call the shots. Do not try to force the situation (meaning don't ask her, don't grab her ass, nothing sleazy dude)! If you guys end up all over each other though, just simply ask, "You wanna go upstairs?" Again, if she says no, play it cool man. If you like this girl(?), that will still definitely score brownie points with her.

I'm sorry the telling her part is vague, but everyone reacts differently to that. You need to find the right timing. I'll give you a hint though, its gonna be after the party but before you guys are naked (when you guys are alone, by the way); but again, its up to you to find that sweet spot. If you would like me to elaborate on anything, feel free to ask.