I just got put on oxygen for COPD, what stage am I in and what is life expectancy, I am 55 yrs.?

Hard to say what stage of COPD your in with the information you typed out. But with the use of oxygen I'd say your in a moderate stage. Just use the oxygen with care and don't go over 2-3liters/minute or else you might stop breathing because your peripheral system will shut down.