Of course. I don't think she really spoke at all until age 4, and it was only with very, very intense behavioural therapy over the course of years that she made any progress at all. To give a sense of scale, my mother quit her job, got a master's degree in the field, and dedicated herself to it full-time (as in - her whole life; not just her whole professional life).
I don't recall a particular "aha" moment, but then, I'm only two years older than her, so I might simply not have been paying attention.
Part of the issue was that this was in the late 80's, and diagnoses were much, much less common then.
If you're curious, the book I referenced, which includes a chapter written by my mother, is at https://www.amazon.com/Triumphs-Early-Autism-Treatment-Cipan... .
You can find my email address if my profile if you'd like to contact me that way. Also, your English was good; you've no need to apologize.