Surely we are who we are at each and every stage of our lives? We do not become, we are and we develop.
Some of us evolve, some settle to stay what we are expected to be by those around us.
Some make step changes - I listened to a policeman recount attending a serious crash and as the engine pushed to the driver, he saw the engine number - the number was indelibly printed on his memory from there.
I have my own personal points of inflection where decisions were taken and, looking back, were not taken by me in free will. Or was it? I was becoming who I am because of who I am then and who I was before.
A lifetime is for living and, perhaps, we drop the time putting in life energy to use to do what we want to do within the time we make available within the 168 rule (Yep, see if this is searched or asked after)