How do you know you're not wasting time? How did you convince yourself? once you have laid out the arguments you use on yourself - can you figure out why they don't work on your parents? For instance - are you assuming a higher likelihood of success for your startup than they are? Or an easier route back in to college if you get kicked out for failing? Do you know something they don't (or perhaps vice versa)? Do they think college is a once-in-a-lifetime opportunity and startup ideas will always be there, but you think the opposite? Or is it perhaps a conflict of principles, like you don't care if you do end up working in fast food so long as you gave the startup your best effort, and they think this would be a terrible failure of everything they ever wanted for you?