What do I say?

I want to ask the guy I like out so bad. He is just too perfect not to think of asking him out. He walks into the room and I'm immediately fixing my shirt, my hair, standing up straighter, checking my make up... ugh he drives me insane. My heart beats 1000 times a second and my face gets hot whenever he gets near me. I've never liked a guy like this before and I'm not sure if I love it or hate it. His jaw line, soft hair, blue eyes, pale skin... and damn his laugh. I know I sound like a love sick puppy but so be it because he looks so hot all the damn time. Not only is he perfect on the outside but on the inside too. He's hilarious, intelligent, kind, and talented. Even before I started like him, or before that when we were just acquaintances he could make me smile and laugh on one of my worst days. I want to grab him by the face and kiss him senseless so bad it makes me dizzy to even think about it. Even through all of that though, I'm scarred to ask him out or just confess how I feel. I was thinking of doing it at a party his family is hosting in three or so weeks but I dont know what to say to him. He would either be my first boyfriend or my first regection and I'm terrified of it being the latter. I've had a few crushes throughout my life and have been asked out a few times, and not to sound elitist, but I've been saving myself for someone who tips my world upside down by just walking through the door. Someone exactly like this guy. So, I'm hoping that you guys could help a girl out on what to say to him since I'm new to this whole scene. I shouldn't be sence I'm in highschool now but I am and I'm nervous as all hell and head over heels.