Things from the past can have detrimental effects upon us and that is to be expected. But, this doesn't have to be your ending.
What you experience during adolescence and beyond can change you for life which I find incredibly sad. For those lucky enough, it affects us very little. But for the majority such traumatic events unfortunately make it very difficult to change the way we act and think in our subconscious. But, this doesn't have to be your ending.
I could say it is all up to you to change, and yes the majority is up to you. But, to be who you once were, or to become something better is easier said than done. However don't be angry or disappointed if you find yourself struggling to see things how they once were.
As hard as it may be, you can get there. You can heal, and you can begin to work towards a life you love, regardless of those traumatic experiences you have had. They may haunt you for life or you may be able to work through them. Whatever the outcome what you were once told, or once experienced, doesn't have to the way it ends.
You have the willpower to improve to the best of your ability, and yes this may not be 100%, but it is still your best and you can try and help choose your ending.