Ask HN: Is it realistic to apply late to YC?

We were quite unsure about applying, as our product was somewhat too vague. After crawling around it, we've finally got something interesting.

Nonetheless, we've realized YC has become more competitive and focused on life/physical sciences. As young international founders building a SaaS product, we've been wondering if it's even worth the time to apply.

I'd understand the "why not?" argument, but timing for a decent application is fairly considerable for us.