Well, I am not new - I have posted before, just not often!
My dd is 12 and hopes to do national novice this next season (similar to L10 in U.S., I think?) - she has been in gym since age 5 and still appears to love it just as much as ever, although I will say that it changes as they grow and achieve higher levels. Definitely more serious now, with a sharper edge - but in a good way. She doesn't seem to be phasing out of it at all, which is also interesting as most of the girls she started with are gone now. As I said, it seems to morph into something else as they grow with their sport - what starts out as a lot of fun (cause they all love it when they're 6, LOL!) either changes into a true passion, or runs its course by age 12 or 13 - depends of course on the gym and its philosopies, too.
At any rate, it would appear she is in it for the long haul (barring major injury, knock on wood - something I always worry about), and my husband and I are along for the ride!
Cheers