If you ever talk about yourself in the past and hear yourself saying mean things like, "I was so stupid," or "I was such a jerk," or "I was so ignorant," that needs to stop. It means that you haven't forgiven your younger self and that younger self is a part of you today.
As long as you hold those beliefs, you're going to be limited now in your own abilities and how much joy you believe you deserve to receive. You'll also be less forgiving to others who act in ways that remind you of your younger self.
You'll get very angry with them and won't accept that they haven't reached a point yet where they see things as you do now. You may try to teach them or punish them but the truth is that they'll only see things when they're ready to and from their experience, not your words.
Back to you. Forgive yourself for not knowing what you didn't know before you learned it. Find gratitude and compassion for that young woman or young man who was struggling along and making some bad choices, unaware of the consequences that would follow. It was all part of the learning process. People act in ways they later regret when they're operating out of insecurity or fear or both. You can't change the past, you can only learn from it and do better today.
You were who you were then but release any bad feelings and you'll free yourself from punishment and free others from judgment. You are who you are now, wiser and better for your experiences, both good and bad.