I held the radar gun at our high schools freshmen tryouts, and the top was 79. 2 could occationally hit 76-77 and the others would sit at 72-73, although it turned out the kid that couldnt hit 70 was the most dominate pitcher last year. Had great command which is much more important in freshman ball than velocity. Your reaching the point where everyone is going to start throwing hard, its the one who can control at least 2 pitches and a 3rd is very useful.
So my advice is that you should be throwing hard enough to get people out.
Good Command=not as much velocity
Bad Command=velocity needed to get away with mistakes
Hope this helps a little.