Did the boot come first? Or did the people on the peninsula invent the boot to reflect where they live?

Maps as early as 500 BC were detailed enough to resemble a boot.

https://en.wikipedia.org/wiki/Early_world_maps

I can't necessarily offer an answer here, but I can give you a bound at least. I was able to find this 1703 geography of the Kingdom of Naples that explicitly calls Italy a boot, so "some time before 1703" can be said for sure

Forma una Penisola, à guisa di uno Stivale, fi come l'Italia tutta fù meditata da Strabone, e da altri Geografi di rigo

Machine translated:

It forms a peninsula, like a boot, just as all of Italy was studied by Strabo and other renowned geographers.

I'm fairly sure the Strabo bit means "we've known it was this shape since Strabo" rather than "Strabo said it was boot-shaped"

To speculate a little more, I think the style of boot that Italy looks like started off as riding shoes developed in 10th century Iran (heels are good for staying in stirrups, apparently). If that is correct then it can't be earlier than the 10th century since there weren't boots that Italy looked like

I wonder if Florida or Italy knew first.

Bet money Pug knows. Real question is, when did a boot, or shoes in general, get stiletto heels?