Here is what OP should do
just accept mediocrity for your high school career and learn as much as you can about training, gradually progressing in mileage/complexity of training. Have fun with High School XC, its a great experience and should be cherished while you still have it. If you really love running you will run during the summers/winters and do whatever you can to get better.
After HS, you can find a college to run at, you wont get a D1 scholarship but there are plenty of D3 (and even D2) colleges where you can be a completely mediocre runner and be on the team, focus on training for an XC/road racer/10k/marathoner, so just go long. At the longer distances, its more about the work you put in just racking up those miles as opposed to talent/speed which are much more important in the 800/1600/3200/5k XC.
You could even run for an NAIA program where they have a marathon as part of their national championships.
Oftentimes slow (even terrible) HS runners who really love running just run a TON after HS and eventually become pretty good road racers/sub-elite marathoners and HM guys.