How do you talk to a guy you have liked for 3 years but he has never noticed you until now and he wants to talk to you constantly. I'm excited but nervous. HELP!!

Be yourself and don't worry so much.

Like odinn7 said, be yourself and don't overthink things.
Get to know him.

Relax, and enjoy the conversation.

Have fun with this. Swag. If you have known him for three years, then there is common ground. Start slow, talk around a soda and you both will get a kick out of the experience and I hope it will be everlasting !