You need to look at your Decree of dissolution first and see how theses issue are suppose to be resolved when you can not agree. You need to follow the decree if it has a method to solve this issue. If it is still not resolved it then you can go to the judge. It depends on the judge how they handle the issue. Some will make the decision based on the best interest of the child and other's will give the power to one of the parents to make the decisions. You need to start the process now if you need the court to intervene because the courts calenders fill up far in advance. I would contact an attorney in your area and bring the decree with.
If your Decree specifies that the matter be addressed by a mediator, then the mediator will decide, weighing all criteria. The best interest of the child is always the basis for a decision.
Please note that I am answering this question as a service through Avvo but not as your attorney and no attorney-client relationship is established by this posting. An attorney-client relationship can only be established through signing a Fee Agreement and paying the necessary advanced fees.