You SHOULD. It puts it in more of a storyline, especially the second season, and makes you more attached to what's happening.
AND HA! I DISPROVED THE AGE THING. The begging of the series is supposed to seem like an eroge or harem/dating sim, and the oldest being 14 would put Higurashi in a very pedo situation. Plus, in an interview with Ryuushi7, he said that he made the series for college students. AND Shion works in a maid cafe. If she was 14, She'd barely be able to work, let alone in a COSPLAY/MAID sexy cafe. And didn't it say that Keiichi was in High School before he moved? Lastly, in their school of 30 kids, they are the oldest. Why would there be all these 6-14 year olds and no high schoolers? That's too much of a generation gap coincidence if you ask me.