which ended up being 14 miles total (no stopping) at 6:24 pace. Is that good for a sophomore in college?
that you can run 14 miles is good.
however....
1. this isn't Fartlek. the definition of Fartlek is quite different to what you ran. this is a good and useful session, but it isn't Fartlek.
2. no one can say anything about you based purely on your average pace for this session. folks run their long runs at a wide variety of paces and the pace that's right for you may not be right for someone else. so, even iif Naw is correct, and many college guys do run their long runs at 5:40 - 6:00 pace we can make two observations:
a. those college guys are probably doing thier long runs too fast.
b. that pace will not be appropriate for a very large number of folks.
IMHO you need to forget this, "is that good" mentality, stop comparing yourself to others and focus on what's right FOR YOU.
train the athlete not the event.
cheers.