Why the FUCK do you need to be 21 to purchase a stripped lower receiver??! I was all excited to start my first build. Ordered an Aero stripped lower and was doing a bunch of research to find the best, most cost-friendly parts. Then, I hear that you must be 21+ to pick up a STRIPPED LOWER from an FFL. That is the dumbest fucking shit I have ever heard. I mean, what's preventing me from taking the lower off of my legally owned AR and slapping a short barrel on it? Literally nothing. Fuck this. Guess I'm either gonna have to wait half a year until I turn 21 or buy an 80% lower and figure out how the fuck to work with that.

Here is my obligatory gun image so this doesn't get taken down.

And yes, I know this is an Arby's you fucking 'tists.

Update: Thanks for all the advice and help. Just ordered two 80 lowers and a jig. Time to get to work boys.