How about after taking out your endowment? Getting sealed in the temple? Becoming a bishop or a stake president or a seventy even?
Yes, even after all those commitments/covenants, an individual is still human and can still make mistakes. And they can all still use the atonement to have their lives and forgiveness restored. But they older you get and the more covenants you make, the more accountable you become. Suggesting otherwise is contrary to the law of the gospel.
And for those who don't believe in our faith or even God for that matter would likely same the same about age/experience. The older you get, the more more mature you should be, the more responsibility you should assume.