5k or not

At the end of last year, my group of friends all ran a 5 miler. They all signed up for a 5k and talked me into signing up. The 5k is approaching fast. It's in less than 3 weeks and I'm nowhere close to where I thought I'd be. I'm now thinking of not enrolling after all. The competitive athlete I use to be its telling me I don't want to do it and not finish with the front. My ego is telling me that I don't want people laughing at me for being last. And my heart is thinking that the few people who I told about the 5k are thinking I knew she'd back out. I have no idea what I want to do.