Much of one's life is spent making up for past mistakes.

Isn't it?

Many people are suffering now for the mistakes they made in the past, but there is no way to start over in life.

"If the ones in front make a misstep, then all the ones following will likewise make a misstep.; etc."

I really regret what I have done in the past, but there is no way for me to start all over again.

Are you suffering for the mistakes you made in the past?