That's very odd. I would be finding a new trainer. Sounds like she competes with collies and doesn't think any other breeds are good enough.
I train/compete with a GSD *AND* a Border Collie. Just because they aren't as fast doesn't mean they aren't sport candidates/can't do it and win. Most don't jump the same height as collies/aussies anyway.
He will definitely speed up once drive training is added after he knows all of the obstacles and sequences closer to two years for a larger dog. You're not in over your head at all!
Danielle, owner of...
Fraggle Rock Collars
Fraggle Vom Richcreek CGC CA
Red Dog's Reconnaissance Man CGC
General Patton Vom Winter Storm