How have you changed since your thirties?

I am reading a book that states that people's personalities, beliefs, and tendencies solidify after their twenties and that people in their thirties and up do not tend to change much. I am sort of hoping that's not the case. Have you found that to be true in your own life? Do you feel like you've stopped changing after turning 30? In what ways have you changed in/since your thirties? E.g., how are you now compared to how you were at 30 or how you were in your thirties?