So, we had no plan in place for my son at school --- neither an IEP or 504 plan. He's now in the 4th grade and although he has sensory integration disorder, he's done pretty well in elementary school. He's quite bright and definitely all should know that having a developmental delay and sensory processing disorder does not mean it has anything to do with a person's intelligence. Straight A's prevail thus far along with accelerated academics added to challenge him.
But, I was recently approached by his teachers to discuss a need for accommodations that might help him in his academic career. At first, I felt a bit conflicted about this because I was so proud of how well he was doing and didn't want any preconceived notions each school year as he got a new teacher. But, what his teachers said made sense. it protects him for the future. Not just elementary school but middle and high school and even college. The things he has in his plan are not anything dramatic but just helpful things like he is allowed to stand in the classroom instead of having to sit in a chair. he's allowed to walk around the class room and take movement breaks to increase his focus. he's allowed a hand fidget and chewing gum. Etc.
Don't be afraid of a plan. It's a way to get your child the things they may need in the school setting to be more comfortable AND more successful.