I was away for a few days and I come back to what I’m pretty sure is a pregnant platy. I would like to know how long until it gives birth.
This is before
And this is after
Sure looks like it. They pretty much always are pregnant if there's a male around or if they've come in contact with one at any time.
I can't say when it'll give birth though. Depends on the fish. Sometimes their bodies will change closer to birth, sometimes not. I recommend looking at the article regarding this in the Platy forum.