When I was young I often thought my birthday is for me only, and everyone will do special thing for me on my day. But on the date I gave birth my first daughter I got a special feeling that, that day is really my special day and will be the day of unforgetable in my whole life. So your birthday is not only for you but also for your mom.
From that I realized my mom may also had the same feeling as me at the moment I was born. You know how much pain moms suffered in a very long time before you come into the world, and also there is some notice in advance about this pain, but moms always happy to suffer this pain to have you in their life.
Since I became a mom I would like giving flowers to my mom on my birthday in order to to thank her for spending hard time to carry me and give birth me, and also to memorize the date she become mom. I would like my kids will also do the same for me when they are old enough to understand about the meaningful of their birthday.