In a perfect world, you'd be held accountable for your actions at any age, and mom and pop could let you carry at any age. Unfortunately, they are liable for your actions until you are an adult.
Given how litigation works... I, as a parent, would allow my son to carry when it was legal. In the home, when he's old enough (4 right now, not yet old enough) he'll know how to operate any and all firearms, and when he gains my trust, may have access to one
when I feel he is ready. As a parent, and thus the one subject to the law, that is
my decison, and to be fair in your case, that's
your parents' decision. If they are okay with it now, and allow you to do as you please, neat-o. But remember, you, under the care of your parents, subject them to the consequences of your actions, and I hope you are level headed and fair enough to dignify that responsibility with appropriate action.
p.s. in Texas, can you buy a gun
before being 18?