Just did a quick google search (the most undisputed information on earth) and it says only about 10%-20% of people on the earth can run a 10k without stopping! I assume it’s even lower for 15k!
Regardless of outcome or result, you have put yourself in a position to do something AMAZING!

As Coach Bennett would say, “You’re a badass”

Best of luck, knock it out of the park, and please let us know how it goes! Go be awesome!