I brought home a female gray domestic shorthair kitten from a petshop
that was full of yiping puppies. A few cats in a rabbit hutch on the
floor in a hallway. This one was small, unsocialized, runtish, sat on
paws, didn't move.

She went into first estrus at 4.5 months. Another heat every 5 weeks,
continued through her first winter. After a year, she was a very small
cat with big ears. I didn't want to get the cat spayed, because I
thought it would interfere with growth.

Then in second winter, she had no estrus in December and January, like
cats are supposed to when the days are short. Instead she had a spurt
of growth that lasted about a month, and became a regular-sized female
cat, normal proportions.

Have you ever heard of a late growth like this? My family had 20 cats
during my lifetime, and I've never seen this. Usually by 16 months
they've become what they're gonna become, I think.