I am not sure of all the questions. But here goes....
1. What is the 2nd amendment? A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed. If your point or her point is that the guns should only be used for militia purposes, frankly that is a laughable assumption. Attached is a decent article for reading, you have to go back to the framers and their use of military or really militias at the time. The military was basically volunteers that brought their own guns and got minimal training at times. The right to bear arms is a right conveyed and supported by the courts.
"Until recently, the judiciary treated the Second Amendment almost as a dead letter. In District of Columbia v. Heller (2008), however, the Supreme Court invalidated a federal law that forbade nearly all civilians from possessing handguns in the nation’s capital. A 5–4 majority ruled that the language and history of the Second Amendment showed that it protects a private right of individuals to have arms for their own defense, not a right of the states to maintain a militia.
The dissenters disagreed. They concluded that the Second Amendment protects a nominally individual right, though one that protects only “the right of the people of each of the several States to maintain a well-regulated militia.” They also argued that even if the Second Amendment did protect an individual right to have arms for self-defense, it should be interpreted to allow the government to ban handguns in high-crime urban areas.
Two years later, in McDonald v. City of Chicago (2010), the Court struck down a similar handgun ban at the state level, again by a 5–4 vote. Four Justices relied on judicial precedents under the Fourteenth Amendment’s Due Process Clause. Justice Thomas rejected those precedents in favor of reliance on the Privileges or Immunities Clause, but all five members of the majority concluded that the Fourteenth Amendment protects against state infringement of the same individual right that is protected from federal infringement by the Second Amendment.
Notwithstanding the lengthy opinions in Heller and McDonald, they technically ruled only that government may not ban the possession of handguns by civilians in their homes. Heller tentatively suggested a list of “presumptively lawful” regulations, including bans on the possession of firearms by felons and the mentally ill, bans on carrying firearms in “sensitive places” such as schools and government buildings, laws restricting the commercial sale of arms, bans on the concealed carry of firearms, and bans on weapons “not typically possessed by law-abiding citizens for lawful purposes.” Many issues remain open, and the lower courts have disagreed with one another about some of them, including important questions involving restrictions on carrying weapons in public."
2. Have there been mass stabbings? Yes. In fact there was a large attack in China the same day as Sandy Hook. Severe gun bans in China and knife attacks seem to be the weapon of choice. Numerous incidents of knife attacks at schools.
3. When is a good time to talk about the school shooting? I think anytime is a good time to talk about it.
4. Is it ok for kids to be killed? Of Course not.
5. We are the only civilized country that has mass killings. That is patently not true. While any killing is too much, per capita we are around 12th in the western world.
Not sure what the other questions are you would like. Banning guns is a direct issue with the 2nd amendment. As it currently stands it is very difficult to purchase a full auto weapon. Age restrictions - fine, but I assume that also means the right to vote etc? You are either an adult at 18 or not. Background checks - fine, no issues there. Not even sure how a loophole even exists. The issue is deranged people will do bad things, regardless of gun bans. This will not magically solve the problem.
The left only wants to take away law abiding citizens the right to bear arms and that will give them more and complete power. Based on their track record with anything else they have tried to do in the past 20 years, I myself am skeptical to give an inch on anything because they will simply move the goalposts. See covid, see healthcare....
A certain gun is not the issue. A magazine capacity is not the issue. The issue is mental health and law enforcement. Make gun crime a severe as possible. Then enforce those rules. Taking guns away from law abiding citizens may make you feel like you have done something but in actuality it will do nothing to prevent tragedy.
If you have other questions I will be happy to respond.