If I were you. I'd go and apply and start searching immediately for another team mate.

Ask yourself. What's the worse that can happen?

I have no xp with y combinator or all of its criteria but a lot of people view one founder as a weakness (this can also bleed over with angel investors too from what I hear). Fortunately you have the tech side. If you want another founder then start searching. If you want a business side person it shouldn't be too hard.

I personally have started as a single cofounder and raised money by the users. Its not nearly as fun but it's doable. If you believe in it i wouldn't let anyone stop me.

My 2 cents.