To solve this question we have to make deduct these 2 years. 2117 minus 1978 will give the answer.
You are 139 years old.
(1668 months are passed.)
From 1978 to 2117 there are 139 years. If you want to learn your age in 2117 (born in 1978) your age is 139.
Let's see what will be your age if you born +1 or -1 from that date.