When the Vilna Gaon was on his deathbed, those with him asked him the reason for his tears.  He held his tzitzis in his hand and replied, “I am leaving a world where for but a few pennies one can perform such wonderful mitzvos, while in the World-to-Come, the opportunity no longer exists.

This, of course, applies to all mitzvos!  

Take advantage now and have no regrets later!