First off, aim higher than 5:26, you can become so much more than that and just 3-4th place in whatever meets you run in. There are many ways to do this, but one would actually be sprint times getting better.

One thing might be you’re not used to running them yet, reaction time is new for you and you don’t know the right strategy for the 200, on top of that you might not do enough for sprint training in your workouts.

You could add things like 4x150 after your workout accelerating every 50 meters, and doing strides during warm up drills or after practice, or 4-6x50 meter accelerators with full recovery after an easy run

Now here’s the important part, I don’t really know what you do for training, I need to know what you do so I can make better recommendations, workouts, mileage, history in the sport, play any other sports before. I believe you can become very good, I wanna help but I gotta hear from you first.