21 to own a gun?

We lowered the voting age from 21 to 18 since 18 year olds were in the military getting their heads blown off and not involved in the political process.

So, if we raise the age to 21 to own a gun, then should we also raise the age to vote since we are telling 18 year olds, they are not responsible enough to own a gun.  This logic would say they are not responsible to vote.  Maybe, not responsible to serve in the military either until they are 21. 

It is not the 2^nd Amendment that is the issue in these shootings, but those doing the shooting. It seems mental health is the issue, but people do not want to raise this issue when they can attack the NRA and 2^nd Amendment.

Listening to the rhetoric after the Florida shooting, guns must be removed from citizens.  Then only the criminals will have guns since they already have acquired them illegally.  The Florida shooter got his gun legally since nobody was willing to come forward and press the mental health issue.  God forbid we identify a person we suspect having a mental health issue for fear of blowback.