Can I sell a handgun to a 19 year old?

P.S. the guy who told me I have to buy it from a gun dealer is the head of the NRA. I believe he is mistaken though. From what I have researched on texas law is that you have to be 18 to own a handgun but on federal law you have to be 21 to purchase it from a licensed gun dealer.

The person purchasing the handgun would be over 21, and it is not illegal to purchase a handgun from a non licensed dealer. So would I be considered a non licensed dealer If I purchased the firearm from a licensed dealer?

I am just asking the legality of it. She would be a family member and she would follow the law by having it on "private property" which would be her apartment, car and house. From what I can tell there is no strict law for transfering a firearm, but I want to be sure. I have researched Texas law for awhile, but as you can tell it is not very thorough in regards to firearm transfers.

You are wrong about possession of handguns at age of 21. http://en.wikipedia.org/wiki/Gun_laws_in_the_Unite...

Texas

Texas has no laws regarding possession of handguns, shotguns, or rifles by persons 18 years or older without felony convictions; a rifle, shotgun, or other long-barreled firearm may be carried openly, however, a permit to carry is required for handguns (issued only to those 21 and older), and they must be concealed. Also, municipalities may not create their own gun control laws (preemption). [34]

I guess I have answered my own question, under federal law it is lawful for a person to sell a firearm within his own state. and Since it is legal for an 18 year old to possess a handgun I see no problem for me to sell this gun in a legal standpoint. After all I am an "unlicensed" dealer.