Except it isn’t, is it. I’m sure there are plenty of ‘young adults’ who are sexually and emotionally mature before their 16th birthday, and plenty more who still aren’t well into their 20s.
Well, there was this young lady I met on holiday once, very *forward* she was, complains there wasn’t anywhere to sit in the part of the caravan park social area we were in, so when I said “well, you can come and sit here” she promptly plonked herself on my lap and put her arms around my neck! Lots of fun, things got a bit ‘heated’ at times, but didn’t, as the saying goes ‘go all the way”
As far as I was concerned, she was my age at least, 18, so you can imagine my shock when she casually said she was 14 in a letter she wrote a while later!