That's me too. I'm leaning towards Gulf Coast, but it's so small. Maybe it's a cross.
I can't tell from your pictures, but does it have a nuchal scute? Somewhere along the lines I learned the nuchal scute is common in luteola's. I know all mine have one, but I have no idea if Gulf Coasts would have it too.
It's probably not a sure thing one way or the other, but it could provide another clue.
All my Terrapene, easterns, gulfs, and three-toeds, have nuchal scutes.I've put it out into an overgrown quarantine pen. If I can find it tomorrow I'll take a look. I hadn't heard that before.