My first few races were difficult. Not the running itself, I'd trained and knew I could complete the distance. The difficulty came with the thought that the "real" runners would be laughing at me. I was slow. I was overweight. "What am I even doing here?" I would ask myself. Showing up at the races took quite a bit of courage.
I was especially nervous when going to my first expo for the Disney Wine and Dine Half Marathon. I'd never been to an expo before and didn't know what to expect. I walked into to the expo and grabbed my stuff. I was surprised to see that I was starting out in the second corral. That meant either the majority of people didn't submit a time or I was faster than greater than three quarters of the people registered for the race. The corral placement made me feel a bit better.
As I've become faster, I've realized that I've been a "real" runner for quite some time. There are elite runners. There are fast runners. There are slow runners. If you run, you're a runner. Even if you run/walk, you're still a runner.
I'm always happy not to be the last person finishing a race but I still think the people who finish behind me are awesome. Especially for long distances, slower people are putting in more training time and more race time than I am. In Disney World I met a man who said he was doing the Goofy Challenge. It would be his first marathon. He said he'd spent seven hours training in one day! That takes some serious dedication. I'm not sure how he did with his races but he was quite excited and I hope everything went well for him.
The runners I've interacted with at races have all been great. Most of the people who are starting in my corrals aren't there to race me. They are there for fun, to beat a personal record, or to support a loved one. No one shows up at races to laugh at other runners.
Don't let mental barriers hold you back!