Laura I know what you mean, scares me how our guys are getting up there. Hailey is 15 yrs now, slowing down, losing her sight and hearing. Thankfully, no health issues. But she'll race through the house and outside, still enjoys sunning herself and spending a lot of time outside when the weather is nice.
Petie and Bobbi are both 13 yrs; Petie is still racing around, he and Who spend a lot of timing play and hunting for whatever critters come into the backyard. I still do a bit of agility with him but frankly he scares the hell out of me. I would trial him more but he wont slow down, still running at 5 yps lol.
Bobbi is still Bobbi, doesn't blast around like Petie but still has his missions everyday to be completed lol.
Sprout is 11 yrs in the fall, I haven't seen any changes in her yet.