I can quickly answer a couple of them without looking up laws:
Age to get a WA CPL: 21
Age to purchase a handgun: 21
Now, I think there's some law that allows ownership of handguns between 18-21, but I'm not 100% sure.
If you can own it, you can OC it. When they tell you to Conceal, inform them that they're instructing you to commit a felony (concealing without a Concealed Pistol License) and if they wish to continue on that course, you'd like to speak to their supervisor immediately.