Many people who stutter have normal or above normal intelligence. HOWEVER, Many people who have an intellectual disability, also stutter. Many people who are globally delayed will have speech delays that often manifest as a stutter. Stuttering alone is not a "learning disability" but many/most people who do have a learning disability also stutter. If you were put in special classes, its probably because you have a learning disability as well, that is exacerbated by your stutter.