I had the same growing up. My parents were in denial of any problem in us, even when we looked abnormally scared around them and did not talk. Back then during that era everything was a secret. It did not help our parents had conditions of their own. That clouded their judgment as well. Taking us for any mental health treatment was not even an option, as they themselves refused to go.
Heck, even the school system did not care. They turned an eye on us. You would think that if we could not speak but a wavering yes or no on rare instances, and looked down and away all the time and avoided all contacts that would throw up red flags to just look a tiny bit deeper. No teacher ever approached me and asked if I was ok. They turned their eyes away from bullying and scandals then too.
I am not sure how any formal diagnosis back then would have impacted me when I was a small child, as I was not diagnosed until my mid twenties with social anxiety disorder. I suppose I would personally have had some relief that I was not facing this struggle alone, and knowing I was not weird but had some condition that explained my behaviors, and that I was not the cause.
At that time we did not have internet, but regardless, I was too lacking of any confidence then to do anything to help myself. Once my parents learned my diagnosis much later, of course they basically said, 'It is all made up. It is in your head.' Unfortunately, yes, they were either a bit ignorant, apathetic or self-centered, to say that, and to think they played no part in that prior lifetime of severe anxiety.
But, to be positive, I learned lots of what not to do from watching and listening to my parents and others, and from analyzing myself and societal members. This gave me strength and a sense of purpose. In that regard I was never a follower, but wanted to start leading, even at an early age. Being so quiet and introspective, and empathetic, helped me focus on details and issues that most miss.