Relationship help!!!

Hey all I'm 17 years..I've been havin a crush on this girl in my class for about two years now and I still haven't asked her out...she calls me her husband after some bullshit my classmates did abt two years back...she dosnt like me sittin next to other girls and talk ( I think it's just for fun that she does that)..she even asked me to be her date at a party a week back which my nasty parents didn't allow me to go (ain't ever forgiving them for that -.-)..every time she talks to me I start kinda blushing and run out of words so I just have drop the talk which kinda sucks..and even most of my friends knw i have a crush on her too coz of the blushing n stuff..last Friday a friend of her n I were talkin and she asked me if I thought Delilah(my crush)was pretty and when I said yes she's like whether I like her.my reply was just a shoulder lift (that yeah maybe kinda thing people do to the shoulders? feel pretty pissed at my self for not saying yes) and she started smilin n sayin that she knows I like delilah and all..so guys u think i should go ask her out?we r kinda pretty close friends eventhough we don't get talk much and I don't want to ruin that freindship between us in case she rejects me..
That's it guys..and sorry abt the long post xD