It's really all up to her and what she's feeling. If she really wants to wait for love to have sex, or at least a vacation, then that's her choice and if he's a good guy he'll respect that.
If he's been asking about sex, make sure she knows not to let him pressure her. It's completely her decision and if she feels like this isn't the time, or maybe the guy, than thats what she's chosen and he'll either respect that or he'll leave. But if he leaves her over sex after just a few weeks (or however long its been) then he probably isn't worth having sex with to begin with.
I didn't really wait to have sex, and I don't exactly regret it, but I do regret my choice of guys. But with my current boyfriend, we only waited a number of days before having sex for the first time
It's really a situation based decision, but she has to know that it's okay to take her time and decide for her self. He'll either understand or he isn't worth her first time.
Good luck.
<3
Sin