But you do compromise as soon as you put age or any other limits on who can and cannot own guns.
Not true.
Minors do not and never have had full Constitutional rights. They cannot vote or enter into contracts or drink alcohol or own guns and are under the control of their parents until the age of majority.
Criminals also do not have and never have had full Constitutional rights. They lose their liberty (prison time), they lose their property, they lose the right to vote and they lose the right to own guns
after being convicted of a crime following the due process of law.
The debate is about the 2nd Amendment rights of law-abiding adults and on that subject there is
no room for compromise.