I had a bf once, we were together 9 months and I just couldn't bring myself to do ANYTHING! He often bugged me for head and stuff but I was sticking by my guns. By the time I eventually considered doing it I realized just how much attention would be on me when I was doing it. That put me off, whereas I think if i'd just done it in the beginning it wouldn't have been a big deal at any time!
We broke up, I was single for a year, I met my bf

and I wasn't scared at all with him. We were seeing each other for about 2 months previous, we got together on 21st December 07 and on Christmas eve I willingly gave my first blow job. I was nervous as and shaking like a leaf but it wasn't bad at all! Best thing to remember is don't try and work wonders the first time, wait until your used to it first.
Along with reassurance that he's not gonna push your head down