If I fail I'll go back to living with my parents/continue college in the fall. Why not just do it from home? I don't really see the benefit of moving to SF. You'll reach Ramen profitability a lot more easily if your costs are $0. You might even start college with something that most students can only dream of: income.
I've found job and contract opportunities are 3-4x more plentiful so you could probably earn a decent income on the side.
I don't think you can live on $1,000/month in SF. The absolute lowest I was able to live on for 1 month was $1,500. I think $2,000/month would be a much better min to shoot for. If you're here for 2.5 months, then you only need to make $2k on the side to have that.
I would recommend trying to get a job or internship and working on your project at night. If it's a website, it will take time to get users and crystallize anyway, and you really can't speed that up by spending 60-100 hours a week on it. So why not spend ~20 hours a week on the site and spend the rest getting paid for things people need right now?
my 2 cents.