Is there a condition where an adult keeps the mental aspect of their child self?

If there is a condition about it, what is it called. Long side-story to explain everything, tis about me. My dad wanted a Harley instead of me in the first place, so I never gotten any help in my life medically except for tet shots. I ended up getting diagnosed with ADHD and as well possibly grew into having dyslexia; all which I discussed with my uncle who had the same condition, described his issues, and I could relate 100% in describing it. I read more about everything and I believe I was put on a leash because I did do everything he told me to do and I didn't have the mental capacity to think for myself, on top of that I believe I was born slow/brain-damaged; which I put literally and not to make fun of myself and be hard on myself. On top of all that, I wasn't naturally helped with this nor did I see any doctors about it because I was believed to be OK by my parents as well as my brother. So I wanted to know, is this the case or did my dad and I have a case of our minds not being able to grow with us; not in a thought way of putting it, but actualy maturing with the body sort of ordeal.