It's completely a personal choice and you can adopt if you were raised in Nepal. Few months may be difficult but it will be fine. I assume you have at least some close relatives. If I am in your shoes, I would retire around 55 and go.
Retired life in USA not gonna be that easy, when you are alone (assuming that kids raised in US will go in their own path and some other state than you live), and old enough to do anything. Enjoy your earning when you are able to.
Life in USA is you are working all the time regardless of your age. Always stressful. Have seen many examples.