I would say, cross the bridge when you get to it. If you can prove your Bonafide with all those proofs officer will believe ( depends on the officer). For negative let experts to say on it. DO not worry
5 years as experts said
It’s a good place to live ( as you mentioned everyplace has its own pros and cons). About your career; can you try nursing? Or teaching?
It’s not mandatory to change immediately
( #experts-plz Correct me if I’m wrong)
Another option, you can request for updated SSN when you apply for naturalization. There is a section on N-400 form.