People at HS games really don't have a good way to measure how far a home run goes - and the field measurements (e.g. what is written on the wall) is not always terribly accurate). Odds are that the original poster is being misinformed by what others are saying as well as the lack of visual clues.
Having said that, 435 is a monster shot. As a means of showing just how far that is, I just went to hit-tracker.com which does do a good job of measuring home runs hit in the major leagues (really neat site).
Taking the average of the 31 homeruns hit on 8/10 (the last day for complete MLB data), the average major league homerun that day was 390 feet. Only 2 of the 31 HRs went more than 435 feet.
08