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.
Why keep the same identity instead of assuming a new one every60 years?
How? I mean, it’s just so easy to get a new ID, birth certificate, social security number, credit history, etc. You just assume a new one.