Luke - black lab - is 25 inches high at 17 months. I'm still dithering about whether to show him or not - but since he's well over the breed standard now am I right in presuming it would be a waste of time? :-(
The breed standard mentions it to be "ideal" height.
I would first go along to a show and have a look, then if you think he wouldn't look amiss in the ring, have a go! :) I have a bitch who is 23 in, over the standard, yet there are some as big as her.
I show my Spanish who is nearly 3 inches over the "ideal" hieght. He's not done too badly either, but there again he does have character and a lovely head and coat which seems to get him noticed, oh and he can move too!
It's not the ideal I suppose to show him but my breeds a fairly rare breed and seeing that he has attributes that maybe some don't have I still show him from time to time and have great fun from him. Bless my little daddy long legs. Won't call any of my others Ickle Man again in case they also become overgrown too :d