I am not encouraging 13 year olds - or people of any age - to marry people outside their age group, I think that's wrong under normal circumstances.

Edit: considering how fast people grow at the age of 13 their age group would be... 14 Year olds max I guess?

Edit 2: duo to how the laws of a nation cover a very wide range of people, I think we should - for the purposes of law - go the safe route and give these rights at 16, if nations normalize 16 year olds having sex then allowing marriage should be a no brainer.

Also someone else mentioned alchohol so I have to elaborate, in my perfect country, alcohol would be banned in all its - non medical - forms regardless of age.

Edit 3 : I have no idea what would qualify as an "abnormal circumstance" before anyone asks.

Edit 4 : I think porn should be banned in all its forms as well before anyone asks.

Edit 5 : I just googled IDF and libertarians and understood the meme, I just saw "12 year olds are not children" and decided to share an opinion that I still hold.

Edit 6 : If you think about it in the context of restructuring society in the way I want it to be - which isn't detailed in this comment - it sounds like a really good idea, but sadly society is corrupted and almost beyond repair.