How to be yourself with this guy i really like? And stop running away?

For some wierd reason, i can be myself with anyone and i mean anyone, i can pratically talk to a chair if i wanted to, but whenever im around him, i just loose myself and get totally shy!! I've never been in a relationship EVER, been asked out a few times, but polietly declined. i've always liked this guy but sometimes, i dont mean to, but i sorta ignore him ( like ill try to avoid eye contact or looking directly at him, because i feel very vunerable when i do), but now i've been beating myself up for this, and i feel like a MAJOR *****, when im not, when in fact ive been told i can be very intimdiating. I am naturally this goofy, funny sarcastic, edgy girl, but when im around him i get nervous so i dont say anything! I also think he likes me too, in fact i think he was trying to make a move last week at school, but stuff messed it up, so we were unable to talk. Anyways i also have a bad habit of being afraid of not being single anymore, cause its the only thing i know how to be, so i always feel like i try to find an excuse to not pursue or be pursued by someone, but this guy is different, and i want to be with him, but how can i if i wont allow myself? Anyways is this all normal, or am i just wierd? lol. And also can someone tell me of ways to talk to guys easily, without being afraid, and dont come off as a *****? And how can i talk to this guy and let him know i like him? as well as not run away?! Would appreciate any and all advice!! :)