To solve this question we have to make deduct these 2 years. 2090 minus 1975 will give the answer.
You are 115 years old.
(1380 months are passed.)
From 1975 to 2090 there are 115 years. If you want to learn your age in 2090 (born in 1975) your age is 115.
Let's see what will be your age if you born +1 or -1 from that date.