Will I set the alarms off at airport security?

It will most likely go off. They have a new type of scanner in most airports now that is more of an xray that rotates around your body so there really is no embarrassment of it going off. They will probably see through the scanner that you have braces and piercings so they won't need to pull you aside. Oherwise flying isn't scary or nervous. Honestly it's not complicated at all. Just keep hold if your ticket all the time and look at the blue boards for your flight number. It's all really easy. Personally it's a lot of fun to fly.