Being the eldest among the siblings is a serious job and almost all the firstborns will agree with this. Since you have the advantage of a few years on you than the rest of the siblings, here are a few reasons why the firstborns are smarter than the younger ones.
2. You know how to do anything right and your younger siblings are always trying to copy your act. They spend their entire life trying to one-up you.
5. You reach all the milestones earlier only by virtue of being elder by years. So whatever your younger siblings do after has already been done by you!