We don't have any yearlings at the moment, but we have a 2 year old that is ground driving well that we hope to hook this fall and then leave until spring. We also have 3 foals about to be weaned (4 months old) that we have been taking over the obstacles in our back yard and one (Bunny, in avatar) is almost a pro already, while the other two are more challenging in opposite ways! No two will be the same. I hope to be able to show Bunny in trail next year as a yearling. I did it with our now 8 year old mare Princess and it gave her a head start on her Pinto Championship which she earned as a two year old. I would do showmanship with her, but more likely I will be doing that with the now 2-year old. I would be a bit careful not to over-do the pivots, and I would let your mini tell you what they can handle. If they seem confused abut what you are asking (rear, get frustrated, etc) then I would do something else. Sounds like you are off to a great start with your yearling!