Life is made up of 3 temporal moments: your past, your present and your future.
It is true that the 3rd does not exist nor has it existed but it will exist (remember you have to be optimistic). I am not a supporter of the slogan live to the fullest the present and do not worry about the future. It is VITAL to live with intensity and full awareness your present moment, this right now, with joy, vitality, without fear or anguish but It doesn't hurt to plan your future a bit: saving is a good habit, for example. It is not that you become a fervent follower of La Virgen del Puño but it is an exceptional habit to save 10% of your income.
As for the past, we cannot do anything to change it. What you can do is live your present with joy, passion and gratitude so that later it becomes part of a joyous past.
I, fortunately, and I hope that you too, have good memories of your childhood.
I leave you a video that takes me back to my childhood in the 80s, all those series and drawings that I saw when I was a child, the second happiest stage of my life because the first is yet to come 😉