At 1.5", the EPT was born this year. It's a hatchling. My page at
http://www.fishpondinfo.com/hatchling.htm gives lots of info on care. It's the same for the EPT as it was for the snapper hatchling I had. Hatchlings cannot be sexed externally. It will be years before you will know if the turtle is female or male. Personally, I would probably keep the turtle around 70-75 degrees F throughout the winter and feed him/her. While you can lower the temperature and stop feeding, there is more risk with that. If it's too warm, they starve. If it's too cold (near freezing), they freeze. I think a lot of turtle experts keep their hatchlings active the first winter. In later winters, those that keep temperate turtles indoors often hibernate them in special refrigerators in plastic shoe boxes (with lots of holes in the lid and an inch of water). That's what I've read anyway.
I have NEVER seen any aquatic turtles within miles of where I live except a few larger snappers crossing the road 1/2 mile away. Snappy (who was given to me) was the only hatchling I've ever seen in person. I have never seen a painted turtle in the wild (just the store). I have seen adult sliders at some park ponds far from home. We do have a few resident box turtles though that we know well. One female we had to treat for a few weeks last year. This spring, she kept plopping into my big pond and digging holes in the mulch (but no eggs that we saw).