Odessa not really a 'small town'
At least by my definition it isn't. It has a population of almost 100,000, according to Wikipedia. I tend to think of a small town as having well under 50,000 residents.
It also has two high schools - Permian and Odessa High. But I think it made a better story to make it seem like Permian was the only school in town, and that Odessa was more like a town of 15,000-20,000 (population).