Mistakes are a part of being human. Appreciate your mistakes for what they are: precious life lessons that can only be learned the hard way. Unless it's a fatal mistake, which, at least, others can learn from.
Wisdom doesn't automatically come with old age. Nothing does - except wrinkles. It's true, some wines improve with age. But only if the grapes were good in the first place.
I've learned that you can tell a lot about a person by the way (s)he handles these three things: a rainy day, lost luggage, and tangled Christmas tree lights.