65yrs old male hemoglobin 12.9 is that ok dr no concern to worry?

Normal: A hemoglobin over 10 is sufficient to function properly. Many GP's have used Procrit (epoetin alfa) for a HgB of 10 where in the FDA has complained that at 8-9 gms someone might want medication but at 12.9 at your age this is perfectly normal.

Mildly low: This is marginally low. If it is consistently on the low side then it does warrant further evaluation for causes of anemia, like iron studies, vitamin b12, folic acid, protein studies, kidney and liver studies, thyroid studies, etc. Really the evaluation is depending on other red blood cell parameters and your history and risk factors!