How do I understand the wisdom of "22 is healthier"?

Be happy and accept yourself. Growth is bitter, and my life is full of troubles. At first, I didn't like Wen Xin's pleasant and sweet way of talking. Pretend! Later, after listening to more, I began to look at myself with joyful eyes, accepting that I am such a capricious and picky variety, not afraid of what others think of me, but very relaxed! Listen to the voice of Wen Xin. That's it!