Good info about that here, Kaleea, from the online journal at the University of Chicago

"40% of 72 individuals who had begun their musical training at age <4 years reported AP. In contrast, 43 (27%) of 160 individuals who had received their first musical training at age 4–6 years and 13 (8%) of 161 individuals who had received their first musical training at age 6–9 years reported AP. Only 4 (4%) of 104 individuals who had begun musical training at age 9–12 years and 3 (2.7%) of 112 individuals who had begun musical training at age >12 years reported AP.

These results indicate that there is a correlation between early musical training and the development of AP."