Birthdays are important for children because of the presents. But they become less so as a person ages until some adults try to ignore the reality of their advancing age altogether.
So, a kid will be quick to point out that they are not six years old but that that they are, in fact, six-and-a-half years old. An adult will hold on to the lower number as long as possible.
It is good to celebrate a birthday because having a party acknowledges that something of great consequence happened on a certain date. Birthdays are important because people are important.
Some birthdays have special significance: The first birthday. The 16th. Birthday number 21 is a big deal, if memory serves. So is the 30th birthday because it signifies that life is over. Done with. All downhill from here on. Which is, sadly kind of true.
The 50th mark in life is the same except worse. One way to deal with being 50 years old is to think of it as being half a century. That’s way better.
There are only a few people in history that keep on having birthdays after they have died. Just a few, because they are notable for something.
We keep celebrating the birthday of Jesus because He is quite famous. Plus, He’s still alive, which is another reason for a party.