As of 0.83, if you run "Build Form" the full 10 years allowed, you start with a 12, 13 and 14 yr old! I suspect that will get addressed later in the beta.
I'll be running them for giggles. Its a UK Combo, they each have a partial jump bar. Wish me luck, named the stable Old Folks Farm.
But, the 10 year form is nice for my initial betting, without getting cheaty on it! I also wanted to see how the lineage feature looked from that perspective. It is intriguing.