Come into your/its own
Definition 1 of 2
Pro Tip 1/3Positive Change
Implies improvement after difficulty or a slow start. 
She struggled at first, but has really come into her own as a sales manager.
Pro Tip 2/3Self-Realization
Suggests a process of growing confidence or recognizing one's abilities. 
After years of training, the athlete came into his own.
Pro Tip 3/3Specific Context
Shows someone or something fitting well or excelling in a particular situation. 
The rescue dog truly came into its own in search missions.