It’s not like there are people checking for immortals, I think it would be flagged by a dmv employee or something when they dont believe a clear 21 year old is actually 150. Let’s assume it’s current day im caught and not bring speculation on what the US is like in the year 2139 is like.
It would be very easy. There are many places where money is all you need. Living in a shithole like the USA is the last place you want to be. Go anywhere you find Russian oligarchs or their kids. There are many micro nations that would gladly let anyone print any name they would like for a fee.
Calling the US a “shit hole” because it’s hard to commit identity theft is odd.
Yeah, there isn’t even a need to move if you are American. Just start a religion based on your immortality, run for elected office, and then the whole system will be so confused that they’ll let you thrive as an immortal deity forever.