Those numbers are in the "borderline" range, so you might need to seek the genetic test. I have no idea if things other than CF can make sweat test results show up in this borderline range. If you got the test from an accredited CF clinic, I'd imagine you'll get good advice from them on how to proceed. But if it was from someplace not fully up on CF, you might want to see about going someplace else.
By its very nature, this website tends to have people with CF reading it, or their families - so you might not hear much her from anyone who got tested and found out they did NOT have CF. Which is to say, you can find plenty of stories on this website of people with borderline sweat tests who DO have CF and it might freak you out if you dwell on it too much before going back to your doctor to talk through next steps.
I hope for the best for you.