To solve this question we have to make deduct these 2 years. 2099 minus 1991 will give the answer.
You are 108 years old.
(1296 months are passed.)
From 1991 to 2099 there are 108 years. If you want to learn your age in 2099 (born in 1991) your age is 108.
Let's see what will be your age if you born +1 or -1 from that date.