I think the biggest thing would be to have a meeting with the coaches, owners and parent. Explain why you left, apologize if it was on bad terms or due to a misunderstanding (it does not make you look bad - even if you are not the one at fault) try to settle if at all possible whatever the previous reasons were between you in private. Once all of this is aired out then wipe the slate clean.
When you go back to the gym, don't try to resume the same place where you were when you left. For example if you were the captain, don't think you are going to walk right back into being the captain. Let the coaches help you transition back into the normal everyday fabric of the gym. It will take some time for athletes(and some parents unfortunately) who were there when you were to regain their trust. Be patient. It can be done, just don't expect it to happen overnight. Don't over sell yourself, just have fun and do what you are supposed to do. Time will be your best ally in this matter.
Lastly, give as little energy as possible to the skeptics and critics. You are not there to prove one thing to them. You are going back because you love to cheer and believe that is the best place for you to be. Maintain your focus on that. I wish you all the best.
