As a 19 year old with no criminal record or delinquent history, would I be able to purchase a firearm at your store or would I be denied due to federal law?

If you are a legal US citizen and an Arizona resident with a current address on your driver's license, as well as a clean criminal record, you should be able to purchase a long gun.

Yes you should be able to, but best to call them.

If you have no felonies or domestic issues and you live in Arizona (with proof), you can purchase a long gun/rifle.

You can purchase a long gun but not a handgun until age 21