Well, it really depends on your training. I spent four years of high school perplexed on how a runner from a rival school could be just so damn GOOD. Always won races, stellar competitor and ended up with a PR of 4:14 in the mile. Produced some sick times and it really wasn't until Letsrun enlightened me with proper training did I realize what the kid had to do to run such times. One of my friends found out about 2 months after track season ended that the kid did upwards to around 80 miles a week. Don't get me wrong, 4:14 is a spectacular time, but it took a great amount of work to do it. Our state champ ran a 4:08 mile and it was found out he did 70 miles a week.
I went through high school bewildered on why this guy was great and I was only a mediocre runner. (4:40 1600M, 9:58 3200M, 17:03 5K). Well, the main problem was our coach was a complete tard when it came to volume. Over four years in XC our week mileage increased from 20 MPW to 25 MPW on the sole fact that we ran faster as we grew older and matured physically.
If you ran 5:30 with no training, I would say you'd have a shot. Meb Keflezighi ran 5:30 in middle school with no training whatsoever. However, if it took you 100 miles a week to do that, then no. It is all relative my friend.