Idiom
grow out of somethinggrow out of (something)
1.
to become too old to be interested in something.
Vinnie did a lot of stupid stuff in high school, but I always thought he'd grow out of it.
2.
to develop from something.
His book grew out of a trip to South America as a member of a government commission.
Etymology: based on the literal meaning of grow out of your clothes (= to become too big to fit into your clothes)