the lead pack of JV XC and your average road race, are like about 5 min first mile. it's quicker than you think. varsity HS XC, college, serious road racing, well into the 4s.
also, as a former sprinter who did XC a couple years, there are two types of 20 min 5k guys. 640 640 640. or 5 7 8. even splits is better running particularly if you have college aspirations or want to extend out to 10k and beyond on the road.
if we're talking a regular gettogether race, you can always spend one testing how far how fast you can go. always be another next week. i would occasionally try running a hurdle or 400m race a little different pacing. try running faster than you often do. some of running is psychological and whether you believe you can go with someone. the other huge chunk is putting in the work to be able to execute.