From Hirschfeld v. Bureau of Alcohol, Tobacco, Firearms, and Explosives, 4th Circuit, Case No. 19-2250 (13 July 2021):
When do constitutional rights vest? At 18 or 21? 16 or 25? Why not 13 or 33? In the law, a line must sometimes be drawn. But there must be a reason why constitutional rights cannot be enjoyed until a certain age. Our nation’s most cherished constitutional rights vest no later than 18. And the Second Amendment’s right to keep and bear arms is no different.
Plaintiffs seek an injunction and a declaratory judgment that several federal laws and regulations that prevent federally licensed gun dealers from selling handguns to any 18-, 19-, or 20-year-old violate the Second Amendment. We first find that 18-year-olds possess Second Amendment rights. They enjoy almost every other constitutional right, and they were required at the time of the Founding to serve in the militia and furnish their own weapons. We then ask, as our precedent requires, whether the government has met its burden to justify its infringement of those rights under the appropriate level of scrutiny. To justify this restriction, Congress used disproportionate crime rates to craft overinclusive laws that restrict the rights of overwhelmingly law-abiding citizens. And in doing so, Congress focused on purchases from licensed dealers without establishing those dealers as the source of the guns 18- to 20-year-olds use to commit crimes. So we hold that the challenged federal laws and regulations are unconstitutional under the Second Amendment. Despite the weighty interest in reducing crime and violence, we refuse to relegate either the Second Amendment or 18- to 20-year-olds to a second-class status.
Yes, that's a published opinion. Interestingly, if service in the militia is key in Virginia § 44-1 makes everyone 16 years old a member of the militia and liable to provide their own weapons when mustered.