When do the children get a say in which parent gets custody?

There is no set age in Pennsylvania as to when children get a say in the custody process.  However, the custody law provides that the "well-reasoned preference" of the child, depending on how they are able to articulate that preference, may be considered a relevant factor in the custody process.  Further, the county that your matter will be heard in may have its own standards by which a child participates in the process.