Anxious about my ADHD diagnosis

Do any other people who were diagnosed later in life (young adult +) ever feel anxious not knowing what you were like as a child? Sometimes I feel like I’m lying to myself - that I wasn’t at all like I am now as a kid and not knowing makes me unsure of my diagnosis. Looking back I do feel like the diagnosis fits me perfectly, but there is still that lingering feeling of unsureness that makes my imposter syndrome go crazy.