The past is filled with rich experience. It has brought you to the present. You have grown through all of that experience. But it can also be mesmeric or addictive. Most of your ideas about yourself come out of your relationship with the past. Guilt, shame, regret can keep you in the cellar. And though we would far rather you felt pride in your achievements, this too can corral you into the past.
Be as a child in the morning. The whole day stretches before you, though for now it can look after itself. You do not yet know who you are, and you do not need to. You are alive, and it is this here and now that matters.