I see a lot of people who wish that they had done many things differently. They are so focused on the past that they are missing the now.
True, we all could have handled situations better. Who can't say that they should have done something better. We get into trouble when we linger too long in the analysis.
Yes acknowledge the mistake, but do not linger there. It is not our mistakes of the past that will bring us peace in our lives. But moving forward that will do that... Picking our selves up after disappointments and doing better the next time.
Don't be discouraged. Life gets better each and every day! Don't regret your mistakes. It is how you will learn. And remember -- ALWAYS MOVE FORWARD!