YANBU at all. I would have been very grateful for you explaining this to my dd when she was little.
My dd's first introduction to the idea of autism came from her best friend when they were both 4. Said best friend had an older sister who had ASD. There was a little boy in their class, x, who later turned out to be on the spectrum as well. Before I was even aware of this, DD's best friend confidently explained to DD that x was a bit different from the other children because he had "a syndrome" and his brain worked in a slightly different way. DD happily accepted this explanation and made allowances for x accordingly.
As they went through primary school, the school did various things to educate the other children about x's autism, including simulations of what it might feel like to learn in a really overstimulating environment, talks about autism from a specialist charity and indeed, opportunities for x himself to explain how he experienced school and some of the challenges that he faced. The other children were incredibly accepting and supportive of x, and eager to make adjustments that would help him. What really bowled me over, though, was when they had their induction talks at secondary school, and x raised his hand so confidently to ask what support would be in place for him as a student with autism. He was comfortable with his differences and confident about asking for support. When a couple of kids from other primary schools began to make fun of him in year 7, even the "cool" kids from dd's primary school quickly told them in no uncertain terms that it wasn't on. And dd and some of her friends eagerly volunteered to help x when he wanted to fundraise in school for an autism charity.
I look back at kids from my own school days who were almost certainly on the spectrum, and think about how incredibly difficult their experiences must have been in comparison, because nobody helped us to understand why they were different or what might be going on for them. Seeing how comfortable and confident x is in his own skin really highlighted for me the importance of educating the other children so that they can begin to understand and respect the differences between people. DD's primary school had a very active and capable "autism champion", which no doubt helped immeasurably. I only wish that all schools could provide the same level of input and teaching in order to develop empathy and understanding amongst other kids while also nurturing the confidence in autistic children to speak up for their own needs.
Bit of a tangent, I know, OP, but I just wanted to say that education and understanding are so important. Of course you should continue to educate other children about autism, and if possible, please encourage the school to do the same. Most children are actually very kind and empathetic if they are given the chance to be, and sometimes, a little understanding of people's differences can go a very long way.