getting off

He couldn't get it up: is it because of me?

first timer
asks:
I'm 17,and I have been dating this guy for like a year. We just started having sex, and the other day we were going to but he wanted me to give him head before so he would last longer...then he could not get it back up. He tried hard to but it just wouldn't. Was it me? Can I just not do it for him or something?...