You're surrounded by other people all the time. And you have to take responsibility if you're the eldest or one of the older siblings, and you're constantly communicating in a way that perhaps you aren't if you're in a smaller family.
When you act in a film, you're inevitably surrounded by people you didn't choose, right down to the set painter. I like being able to pick the family I'm waking up to in the morning that's going to make this group effort to tell a story that applies to what's interesting to me at that stage in my life.