21 or 22.
If you were born in 1987, you would be 23 today.
At the end of 2011, you would be 24.
On that person's birthday in 2010, he would stop being 22 and start being 23. That's speaking purely hypothetically and subjunctively, of course.
Someone born in 1983 would be 27 years old in 2010.
They would be 22 or 23.
As of October 2011, someone born in July 1987 would be 24 years old.
21 or 22.
If you were born in 1987, you would be 23 today.
One day old on 19 January 1987.
25
At the end of 2011, you would be 24.
23 years old.
It depends on when you were born!
21
25
24 or 25 in 2012.