Is it possible to be dumb and go college?

Yes, it's possible. "Dumb" isn't a precise measure of academic ability. Colleges admit students with a wide range of abilities and learning styles. While high academic achievement is generally required for admission to selective colleges, many colleges accept students with varying levels of preparation and academic skills. Some colleges have extensive support services for students who need extra help. Furthermore, "intelligence" is multifaceted, and someone might excel in practical skills or creative fields even if they struggle with traditional academics.