At 69, memory issues are common, but you say this has been going on for your whole life. There are many possible medical reasons. I hope that you talked to your primary care doctor about it long ago.
There are also possible psychological explanations. Chief among them is that life changed dramatically in some way at some point in your life that made memories of what happened before it no longer relevant. You see, memory isn’t like a video library. What we remember is selective. Usually, memories in some way confirm how we look at the world today.
If you were seeing me in therapy, we’d be talking about why this is bothering you so much now that you wrote to us. We would look at whether something happened that changed your perceptions of the world so much that you discarded memories that didn’t fit. We might also discuss whether it would be helpful to you to try to connect with childhood friends for some reminders about what once was. It’s complicated.
If this continues to trouble you and your medical doctor sees no reason for memory lapses beyond what is typical at your age, then by all means see a therapist who can explore it with you.
I wish you well.