This time will not be counted against the time granted you upon this mortal plane...
As the earth completes its orbit not in a year, but in 365 days, 5 hours, 49 minutes, and 16 seconds adding a day every four years is somewhat off... 42 minutes and 52 seconds every leap year to be precise.
In order to compensate for this extra 3 days every four hundred years, years that are divisible by 100 but not by 400 are not considered leap years despite the fact that they are divisible by four. Unless you are planning to live until 2100 when we take back this extra time you may consider it a bonus, don't say we never gave you anything. If you are alive in 2100 just consider yourself out of luck.
This day used to be on February 24th and was known as Bisextile day in the third century, but we had to rename it do to an unfortunate misunderstanding with some fundamentalists. February 24th in Roman times was the sixth day of Kalends and was doubled every four years after the Julian reform, it was called bis sextum, literally double-sixth.
If you are a Leapling... Happy Birthday!