I have mostly identified first with my local region, despite having moved around a lot. For a long time, after first moving away from where I grew up, I continued to identify with that region, but when I eventually got to move to areas which were better suited to me culturally, my sense of identity shifted. Now where I grew up is secondary or tertiary and local region is first.
"America" is a vast area. Too large to be considered a cultural region.
For me, in particular, I grew up in New Jersey. My primary culture was South Jerseyan, heavily influenced by Philly. Then New Jerseyan, more influenced by NYC. Then Northeast and Mid-Atlantic. Then American.
The culture did not suit me, though, and I have spent many years in the Pacific Northwest now. So now, I identify primarily as someone from the Pacific Northwest, having spent time in both Washington and Oregon--Mostly Seattle, but also kind of the boonies for a little while. I am a Pacific Northwesterner first, a New Jerseyan second, and an American third.
That makes sense, if regional kinda works for your scenario. It wouldn't really for mine, so I feel the need to go straight to "American", but your description helps me see how that wouldn't work as well, as in like not be as suitable, for someone else. Thanks for sharing your story:-).