If you live in the same school district as your parents, you might be able to get your son back. You are going to have to argue that there has been a material change in circumstances since the last order was written (which there probably has been) **AND** that the requested change is in your child's best interest. You're going to have a hard time on that point.
Have you been exercising all your visitation rights? Have you met with your child's teachers to know what classes he's taking, how he's doing class by class? Would your child have to change schools if he came back to live with you? These are all factors that the court will consider.
You are going to have to hire an attorney to win this case.
I agree with the other attorney's advice, and would add that if you are not exercising standard visitation, or if hat is not ordered, you will need o begin here. This will make the transition easier or he child, if you do win primary conservator, and show the court you care nough about the child's emotional health to not just yank him out of the only home he has known.
Please consult a local family law attorney! Many attorneys, like myself, offer a free consultation.
This answer is general information which does not establish any attorney-client relationship between the person asking a question and the person answering, or a duty to respond to ongoing questions; nor is it intended to replace competent legal assistance in the jurisdiction where the matter/issue arises or is before a Court.
I agree with the other attorneys but would like to add that you should work on establishing a solid, loving relationship with your child. Keep in mind, your child can decide where he wants to live when he turns 12. So if you can't win now, start planning to get him back later.