I don't think you're 1300 USCF... talking about in real life clubs, people usually use OTB ratings.
Average for ALL high schools, hmm. 1300 USCF might be average. The best high schooler in a large city is probably more like 1800, and the best teenager in the state will usually be a titled player... but there are a lot of bad playres too of course, so 1300 might be something like average for best player in a school.
I'm my high school's board one in 8th grade, aprox. 1350 elo. Is this about average, or am I slightly below? Been playing for one year btw.