How soon can I apply for an internship?

I am 99.5% sure I will get plenty of flack for this question, but when is the soonest I can apply for internships? I am starting undergrad in a month, and I am too eager to have an opportunity to work myself to death (no sarcasm). I know you generally intern around your junior or senior year, but if there is even a small chance of an internship before that, I will give it my best shot.

Thanks and best regards,