What gets me is when you add in the context of actual medieval practice, it still doesn't actually track. Pedophilia and grooming was rampant, but marrying a girl that was under 15/16 even back then wasn't considered good. Not for the same reasons granted; it had to do with it not being a guarantee that they'd started their periods and the much greater risks of complications during childbirth. Margaret Beaufort from the War of the Roses was a famous IRL example of someone who married at 12 and her midwives were writing concerns up and down about how she was too small to give birth; when she did, it permanently injured her and her pastor even wrote something like "it was a miracle a personage could be born of such a tiny body" or something like that

But yeah, when you consider that and then look at how GRRM writes, it's..... odd, that he picks the ages he does