I decided to research further whether birth order within a family actually has effect on personality or behavior. It has long been believed that the first born in a family tend to achieve more, middle borns tend towards diplomacy, and later borns tend to take more risks. However, when I did more research, I found that most of these claims were exaggerated.
I read the article "How Birth Order Affects Your Personality" by Joshua K. Hartshorne on ScientificAmerican.com. To first address the claim that first borns tend to achieve more, he gave the widely used evidence that 21 of the first 23 astronauts were first borns. He digs deeper on this fact, actually finding that birth order only really creates personality differences among siblings in they are from a very large family. 21 of the first 23 astronauts may have been born first, but, for example, coming from a small family where there are only two kids, those astronauts had a 50% chance to be born first, whereas a child from a five kid family has only a 20% chance to be born first. Family size also affects personalities because of how the resources of the parents must be spread out. More children means more resources need to be used, and each child may not receive the same benefits that children with only one sibling receive.
Personality has less to do with birth order, and more often can be attributed to family size.