I agree pups will be pups
Since this is in the agility area if you are looking for jumping drills for you pup or older dog this is how I teach them to find jumps and the uprights. When I am working a young dog like under 4 months I will take the bar off the jump and do it with no jump bar. When the pup is 4-6 months I will put the jump at 4". Then at 6-10 months 8" is ok but again I do not jump puppies much just little exercises like this are just fine.
When I work my older dogs I always work them low when doing jumping drills so not to jar the joints repeatedly. When they are old I will work on jumping full height but it is more important to work on find the jumps without your help than it is to learn jumping at an early age. Now some trainers disagree and will wait to do any jumping till the dog is 18 months old then will jump them full height right away.
I am more cautious and I want my dogs to be able to run till they are old not till about
7. Over jumping a dog wears down the body and they will have a shorter career. Not all dogs are built like a Border Collie.