Normal sim lifespan when you're doing a horse ranch is definitely too short.
In real life it does not require 15 minutes to saddle a horse. Feeding a carrot, 10 minutes? Riding two blocks to the Equestrian Center, 45 minutes? Please. Try for Foal can easily chew up half a day, what with multiple hangups getting them into the stall. Then there's the Jockey lifetime wish and achieving the three International wins, which can take weeks in and of itself. Until EA can work out these inconsistencies, my advice is to turn off aging, set intermediate goals, and age Sims manually as appropriate.
In the case of competitions, in real life a single season might include 10-20 competitive events. It's ridiculous to thing of a sim going from adult to senior in the space of only a few seasons.
Personally, I always disable aging. Not only does it affect me emotionally when a sim dies, I also enoy playing truly epic games, where my sims might have a number careers, raise several children to adulthood, and hang around long enough to see their grandchildren married, with children of their own.
I wish there was a way to slow down the clock relative to everything else.
