Ok...
At the federal level, there's no restriction saying an 18 year old can/can't possess a handgun. States typically set that age.
What Louisiana cannot do, and is not attempting to do, is allow 18 year olds the ability to purchase a handgun. An 18 year old still can't buy a handgun, only a long gun (rifle/shotgun)
This law only allows an 18 year old the ability to carry concealed (provided he/she is legally able to do so); an 18 year old still can't buy a handgun from an FFL.
Louisiana was already an open carry state for 18+ year olds. Oddly, Louisiana is also one of very few states that allow legal possession of a gun by someone under 18 (17 to be specific)
So in reality, not a whole lot changes. Thugnificent and Ray Bob the Meth King and their cronies have been carrying concealed for decades. If you were worried about it before, stay worried about it moving forward 'cause the same niggas you were concerned about are still gonna do the same shit because they're criminals.
Now... Having said all of that, I'm pretty much against this law. Nothing good comes from allowing 18 year olds the ability to carry concealed. The racial aspect of it says now whites now have the ability to kill Black folks wherever they may find themselves if they can justify "feeling threatened". And, well, they're white so their fear will almost always be justified in court.