For any given year after 2000, your age on your birthday will be 11 more than the last two digits of the year, and one year less prior to your birthday.
For example:
In 2015, you would be 11 + 15 = 26 on your birthday.
Before your birthday in 2015, you would be 25.
21years.
1989
1989
If you were born on The 21st of December on 1989, you would be 20 years old 19 years old, you would only be 20 on the 21st of December.
20
21
20
21years.
25
You could be born in 1988 or 1989, depending on the month.
You would be 21 years old
Twenty-four 1989 + 24 = 2013
Rochelle was born in 1989 - (current year minus 1989)
Vanessa was born in 1989 - (current year minus 1989)
1989
1989
25