To solve this question we have to make deduct these 2 years. 2100 minus 1977 will give the answer.
You are 123 years old.
(1476 months are passed.)
From 1977 to 2100 there are 123 years. If you want to learn your age in 2100 (born in 1977) your age is 123.
Let's see what will be your age if you born +1 or -1 from that date.