Why not apply to YC? Worst case, you'll spend a couple of hours answering questions on the application, then get a rejection email. On the bright side, simply answering the questions can help hone your idea and execution. If you do get an interview, great! Then you have an opportunity to meet some YC partners, applicants, and alumni. If you're turned down at that point, feedback from the partners will be personalized, and you'll have gained experience interacting with investors. If things go well and you get an offer, then you can accept or refuse based on the information gleaned from the whole process.

If you're unsure about applying, I recommend doing so. No matter what happens, you stand to benefit.