How old was Timothy in the book of 2 Timothy?

Timothy is over seventy, probably early eighties, but you can never tell

The consensus of biblical scholars and of most theologians is that 1 Timothy and 2 Timothy were both written during the first half of the second century and therefore long after the death of Paul

another 60

Timothy was the son of a Jewish mother, who had become a Christian believer, and a Greek father. Timothy's home was in Lystra in the Roman province of Galatia in what is now Turkey. In his letters...

The book between 2 Timothy and Philemon is Titus.