Well, it's another leap year! This is one of the strange things about the calendar: the creation of a day that occurs only once almost every four years. (Remember: there wasn't a February 29, 2000.)
If you were born on this day, then a very Happy Birthday! to you. If you were born on this day in 1976, you're "9". In other words, you're older than me, in terms of years, but I'm older than you in terms of birthdays-on-your-actual-birthday.
(And thus we understand the complete construction that the calendar is.)