The plan is currently to do this every month, so even if you feel you aren't the best modder, it's worth entering this one and honing your skills. You might not win this time, but in future events you'll have a better chance
Also, I believe the hardest part of making a mod is coming up with the idea for it, rather than actually making it. So as long as you feel you are a creative person, you should be pretty good at modding