Dear Allison,
Welcome! I am so sorry to hear of your diagnosis, BUT now that you have it, you will be so much healthier....now and in the future. At the same time I can only imagine at 18 what it must feel like to be diagnosed with CF and then reading all the horror stories and fearing that is your destiny. CF is unique and everyone's manifests differently. There are several on this forum in the 60, 70, etc. And that you are just being diagnosed now shows that it hasn't affected you too severely, but over time things can worsen, so it is important to keep up with the treatments now to prevent that from happening. That said, you are one of the "lucky" ones with the R117H because the mutation can be partially fixed by a drug called Kalydeco which the FDA just recently approved for us in your mutation. The following link gives you info on that.
http://investors.vrtx.com/releasedetail.cfm?ReleaseID=889027
But it gets better: There is a second drug when added to Kalydeco fixes the CFTR function even better and Vertex is starting a trial this year for those with R117H + df508.
So the long and short is that you have every reason to believe you will live a long, healthy and happy life with all the dreams you had possible. You need to take care of yourself in ways other 18 year olds don't, but
you have the hope of everything. Also, doctors have figured out how to "splice" out a mutation in the DNA (or RNA?) strand and insert a "good" gene. This is very very early research, but by the time your 30, you well could have "normal" DNA!
These two links tell you about how R117H 5T seems to affect folks with df508:
http://www.cftr2.org/r117h.php
http://www.cftr2.org/mutation.php?view=general&mutation_id=6
Finally, if you are in the US, you should immediately call and ask the doctor for a script for Kalydeco. I am not sure the status of Kalydeco in other countries. Also, I am not sure why you aren't on any other inhaled meds, such as a bronchialdialtor and Pulmozyme (instead of Mucinex!!), at a minimum. Maybe the doctors didn't want to overwhelm you, but I'd ask about the treatments more next time!
Good luck Allison and let me know if you have any questions!
Love