Like every vehicle out there people also have a rear-view mirror. You and I use this mirror to look back at our past.
However, this mirror is of not much use for building a great future.
The main reason behind this is looking back at who we were and what things we've screwed up deprives us the courage to move forward and achieve something.
You get bound by the thoughts that you are not up to the level to be the successful person that you've always dreamed of because you never were.
It's a very common phenomenon.
The best thing you can do is to put a cover on this mirror of yours. Just block it. Don't use it.
Just because you were unable to achieve something in the past doesn't mean that you can't achieve it in the future.
Level up and you can achieve anything.