Nerves ~~~~

So, this is my left leg. I know, what a glamour shot, right?!? At scouts a few months ago I fell during a flag ceremony... (LONG STORY)... I ended up hyper-extending my knee and breaking my leg right below my knee. I am healed up and all is well ~~~~ maybe.
I'm getting nervous about the Pacific Crest event and wondering how my leg is gonna fair. I walk now and my knee tries to go backwards a couple times. I'm hopin' all will be well. Walking 5K sounds doable but at 4700 feet above sea level kinda freaks me out.
Maybe I should rent an oxygen tank to strap on to my back...

Only eleven days... (yikes!)