The others already said it but stutter isn't a symptom of autism, its just a comorbidity, you might misunderstand if you know a person who stutters superficially ( and if you don't know much about autism ) but it doesn't tell much, i know people who stutter that don't even remotely appear autistic, you should read more about the actual symptoms. Besides people who stutter also often have other mental illnesses like anxiety disorders and it can make you feel and behave like an autistic person to a certain extent, there's a lot of blurry lines here, that's why even professionals sometimes mistake one for another, but you should try to get a diagnosis if you can, it's the only way to know, self analysis is important but very biased.