It's not obvious to me how this does not handle leap years. If your birthday is leap day, and it's not a leap year, then on February 28 it would not have been your birthday yet, and on March 1 it would have been. If you birthday is February 28, then on February 29 of a leap year your birthday's in the past, and if your birthday is March 1, then on leap day it hasn't passed yet.

What am I missing?

RD Francis