word choice - What noun or a phrase would fit well to refer to a person's "placement" in the family?

What noun or a phrase would fit well to refer to a person's "placement" in the family, among his or her siblings?:

She is the fourth and the last child in her family. Her siblings are all brothers and the youngest one is ten years older than her. Girls of this family status are usually more mature and less shallow.

How can I ask a person in which order in his family among the siblings? is seeking how to ask a question about one of the constituent factors, while I'm looking for a term that would refer to a particular combination of constituent factors.

To use an example, letter "l" is the third letter in both "owls" and "delamination". That that letter is the third one is a constituent factor that plays its part in both combinations.

However, the combinations are quite different:

• one word is a combination of four letters, the other one is a combination of twelve;


• in the first combination there are more letters preceding "l" than those following it, in the second combination it is the other way around;


• in the first combination, letter "l" it is surrounded by consonants, in the second combination by vowels;


• etc.

Answer

A common expression at least related to this is birth order.

From a psychological perspective, birth order is a contentious theory, and I personally don't put much stock in it. Wikipedia opens its article by saying:

Birth order refers to the order a child is born in their family; first-born and second-born are examples. Birth order is often believed to have a profound and lasting effect on psychological development. This assertion has been repeatedly challenged ... Nevertheless, the notion that birth-order significantly influences personality continues to have a strong presence in pop psychology and popular culture.

From an English perspective, however, you could say:

Girls of this birth order are usually more mature and less shallow.

The term says nothing about the spacing between siblings, but your example mentions the ten-year gap explicitly, so it would still work in that context.