My first race were the old Nike Races around either 5 miles or a 10k.
In 2006 the Nike Run Hit Wonder (where they had 1 hit wonders perform). I guess that wasn't as appealing to the performers so they changed it the year after to be the Nike Run Hit Remix in 2007, then the next year it became the Nike Human Race in 2008 this was a pretty awesome race because Kanye West performed at the end. After that I stopped attending these races because they started to get more expensive but more lame.
The 2009 race was held at midnight, and fyi, running around 'that' part of LA is not safe at night, oh and also NO BAND & no music. More $ and less goodies.. no thanks.. They haven't hosted another one of those races since.
I wasn't a consist runner back then. I trained a few months before the 'big' race, and take a significant amount of time off. But I always remember how STRESSED I was over that those races. Running 6 miles? WTF?!! I would train diligently and get my miles in.
in 2009, I decided to go for the Big Time, and do... The Orange County Half Marathon.. 13.1 miles.. It was the biggest challenge ever. I thought I could never run more that than ever, but after I did I race, I went on to run a marathon the next year.
Its funny how quickly perspective changes.
This weekend I have a 13.1 race coming up, and I can honestly just go out and run it, without stressing about "training" for it. I mean I'm training all the time anyways, but Now I can actually Enjoy myself. 13 miles is close to a normal maintenance run, and 6 miles are my "easy" runs.. just a few years ago, 6 miles was insane to me.
So if you have a big race coming up and you're worried about it, dont worry too much.
You'll finish, look back and think, "hey I did it, and I can do more!"