just wanted to see if anyone would have a problem being trained by someone of my age.
It depends on two things.
One. What it is you intend to teach? If it's just basic firearms handling and safety.....maybe. If you're planning to teach classes beyond that, probably not.
Two. Again depending on what you're teaching. Before signing up I'd wonder what, practically, you're bring to the table that I couldn't get from another instuctor who also has years of experience. If you're 22 and ex-Delta or SEAL, I respect everything you can tell me....although I'd wonder why at that age you were out. If you're 22 and have simply been to a bunch of classes, odds are I'd keep looking for the caliber of instruction provided by instructors at Gunsite, Thunder Ranch and the like.
There are all sorts of levels of instuction. And, you may have answered your own question. Fill a niche that's untapped. Younger, qualified, people teaching younger unqualified people. Might be an excellent idea.
It's not so much the age, as the experience. Excellent places to get that....police departments, SWAT teams, and, depending oh what you do there, the military.
Don't forget your liability insurance.