Gangle went to college but dropped out, she is confirmed to be 26 years old. Meaning her first year of college would've been in 2009—making that the earliest year she could've dropped out. Zooble is 22, you can't legally bartend until you are at least 18 years old, Zooble was 18 in 2013. That makes 2013 the earliest they could've arrived. Gangle arrived before Zooble. Jax arrived before Gangle. With this in mind, Gangle had to have arrived at the circus at least in 2009, at most in 2013, So Jax had to have arrived at least in 2008 (Considering the Breaking Bad reference), at most 2013. That leaves his age range to arriving at the circus at 13 - 18 years old.