To solve this question we have to make deduct these 2 years. 2100 minus 1980 will give the answer.
You are 120 years old.
(1440 months are passed.)
From 1980 to 2100 there are 120 years. If you want to learn your age in 2100 (born in 1980) your age is 120.
Let's see what will be your age if you born +1 or -1 from that date.