This is what I've got for the history. (I'm not really sure if we are using identity-first only or a mix of terms. What I've typed can be changed.) I need to maybe shorten it, but for now, how's this?

In 1970, an organization known as Autism Society saw the need to raise public awareness on autism and provide support to autistic people. Because of this, the Autism Society founded Autism Awareness Month. Every April, Autism Awareness Month is celebrated to help educate others about autism.
Autism Acceptance Month was a different name later proposed by autistic advocates to change the negative images of autism sometimes shown in autism awareness media. The world may be aware of autism, but acceptance is needed too since there is still a lot of discrimination and bullying toward those on the spectrum. We need both because they work together.
To show your support, you can wear red on April 2nd (World Autism Awareness/Acceptance Day). Only by working together can we create more understanding about autism and help autistic people!

Sorry for not having it done a bit sooner.