there is nothing wrong in being childish at times, it keeps your inner child happy!
if you did not get the opportunity to fully have a proper childhood as a child your inner child will not have grown up as quickly as the rest of you, and therefore is still seeking the experiences it feels it did not experience when you were young.
mine used to come to the surface whenever i had to attend training workshops, i would feel little/vulnerable, suck my fingers and just want it to be over so i could go home and cuddle my teddy, my therapist at the time suggested i try taking teddy in a bag with me and whenever the feeling started i could stroke teds ear under the table, it worked and after a few times i did not need teddy to come with me anymore!
I still like being childish at times, usually when i have big decisions to make i take time out in private to be a child again for a while before the 'adult' me can confidently make the decision.
if being a child for a while helps you feel ok then go for it in the evening, just keep reality that you need to be an adult again in the morning, don't let your inner child rule the whole time, but giving it a designated time each week or so will help it feel ok enough to let you feel and be an adult the rest of the time
you wouldn't ignore your leg if it were hurting would you so why ignore your inner childs feelings when it is hurting?????