Agreeing with the others - L5 at that age is all fun - my younger did L5 at 8 and 9 (he has a summer birthday) and was middle of pack, made regionals even in the competitive 9/10 group - a couple medals only (pommel). But he had a ball! He tends to be the kid who can" do" bonuses but shouldn't (LOL) at meets, and has learned that over the years, where his late starting older brother understood the score game much earlier and holds out on his skills until they are really good. My boys both did "old 4" which was more complex than new, and the young one repeated it (6 and 7). That's the norm here. The talented young boys train up while still often repeating (my kids repeated cuz they needed too...).
There are some skills (muscle up) that are easier for the younger kids, but as they hit L7-10 there are a ton kids need puberty and the testosterone that comes with it for. I really love the boys system of bonuses so that everything builds and there are new skills even for repeaters....
DS L7 still can't do a muscle up, by the way....FHS-FT vault, great L7 rings with all the bonuses, PBs with bonuses, both giants and pirouette on HB, etc - but no muscle up - its sort of a gym joke - you know, the kid whose working iron crosses and can't muscle up....go figure....