Age is no guarantee of maturity

आदौ चित्ते ततः काये
सतां सञ्जायते जरा ।
असतां च पुनः काये
नैव चित्ते कदाचन ॥

- पञ्चतन्त्रम्

In case of virtuous people, old age sets first in mind and later in body. On the other hand, the body of a wicked person keeps aging but his mind never matures.

Wisdom doesn't necessarily come with age.
Growing old is mandatory.
Growing up is optional.
Age is no guarantee of maturity.