Interesting topic......
I tend to think that birth order role assignments are just a huge oversimplification. I am one of 2 daughters, second born. My sister is a very outgoing, "loud", strong-willed person. She is also a recovering addict/alcoholic. I am reserved, sometimes shy, typically very quiet. I did not do as well in school as my sister, but I typically respected authority and did not get into much trouble.
My parents are not alcoholics, but my mother is an untreated ACoA......
Hugs, HG