Seriously.......it doesn't have to be a problem if she knows what she's doing. My guess is that she is young and inexperienced.
So she can't deep throat you. That doesn't mean she can't rock your world by taking as much of you in as she can. And using her tongue ....especially on that little sensitive spot on the underside :wink:
Let her take it slow......let her know what feels good. Don't expect perfection till she gains experience. TELL HER WHAT YOU LIKE....
As she gets comfortable with it....she'll probably give it to you all the time!