Is birth order destiny? In some ways yes. Unless you take the time and energy to understand it’s impact, birth order, and your experiences in your family, will determine your adult character traits and the way you relate to others.
Fitst borne and only children are more independent and self confident. Almost all our Presidents are in this category. The downside is a tendency to be self serving and less attentive to the needs of others. Middle children are often “lost”, with less direct parenting. The tend to have less forcefulness and are more comfortable in a group. They have better people skills and are slated for middle management. Last children are more likely to be infantalized or “spoiled” and often held onto by the parents. They have trouble leaving and tend to be entitled.
These are generalized trends, but hold up in large numbers studies. Are you doomed?! No! Knowledge, introspection and psychotherapy are tools to free you to clear you path to your best life. And as parents, you efforts to treat each child as a unique individual helps them to overcome any limitation. Your destiny is yours.