It really shouldn't be even close to a defining moment in your life. There are a myriad of routes to building a successful company, and YC only accounts for a tiny percentage of them.

It's easy to miss this fact if you spend a lot of time reading Hacker News, but it's true. So use this knock to re-evaluate and analyse by all means, but YC is far from a guarantee of success: if you were going to be successful after being accepted through YC, then you will inevitably find some other path to the same destination.