Moms of kids with autism!

So my son used to say dada, Ajax (our dogs name), why, and shake his head no. Now he doesn’t say anything.. sometimes I think he says why but not how he used to. Everything I have found seems like it might be an early sign of autism bc he is only 15 months. (which is okay id just like to know so I can get him necessary resources). I told his pediatrician and she said some boys do that and he’s too young to be screened for autism. But isn’t the whole gender and talking thing a myth? Like it gender doesn’t determine how much or when a child talks. I’m just wondering if anyone has any experience with their kids possibly doing this and having autism.