The eternal age of Krishna is 15 years 9 months 7 1\2 days.
In His Bhauma-lila, He appeared in Gokula and He stayed there until He was 3 years 4 months old.
Then He went to Vrindavan (Chatikara, Ral, Vasanti) where he stayed until He was 6 years 8 month old.
Then He went to Nandagram where He stayed until He was 10 years 7 months old.
Then He went to Mathura where He stayed until He was 28 years, four months old.
Then He moved to Dvakara. He disappeared at the age of 125 years, on February 18th 3102 BC, that is the day Kali-yuga begun.