Great info, thank you so much!Does it say which pennywort? There are several plants with that name, at least two of which grow in Florida.
it isn't dollarweed, which is one of the two. It could be Asiatic pennywort although it doesn't look tightly enough packed together to me. Are the stems hairy at all?
I got a false read on the dollarweed pennywort myself when I looked for it--dollarweed has very rounded leaves and this isn't it. I did find something that seemed more likely to me, which is fig buttercup (lesser celandine). Buttercups are in the rananculus family, which you will read many warnings about. Unfortunately these warnings are wrong and based on bad science, Russians eat tons of buttercups in their native region. TONS. I would be delighted if they grew near me.
Either of these pennyworts and buttercup are safe to feed but since you don't know which it is you should wait to see if it flowers. Yellow flowers would mean buttercup.