Many psychology studies have demonstrated quite definitively that your past behavior is a strong indicator of your future behavior. This is not an absolute fact but does prove to be true in the majority of cases.
It is possible to change our base behaviors, that is those go-to actions that define our personality, but it does require a lot of effort to do so and you really need to be motivated.
Who Are You?
In essence, we are defined by what we did and where we have been. What we are going to do will not actually define us until it is done. Aspirational behavior is key to forging your future but until it is the past it does not define you.
Knowledge and experience are valid indicators of individual value, however, what we actually achieved is a much more definitive measure of our capabilities and the things we will be able to achieve going forward.
In essence, you are what you were, sad but true.
Laying the Foundation
Given others will judge you on your past accomplishments it is important to plan your activities and the way you behave so that you are consistent with how you want to be perceived.
Once the foundation is laid changing perception can be a long and slow process, if even possible.
Taking missteps as you find your way through your life journey is unavoidable but on the whole successful achievement of your goals requires behavior consistent with the way you want to be viewed.
Remember what you do now will strongly influence what you are able to do in the future (no takebacks).