Hi. I understand your concern. I graduated from a very liberal high school in Germany and was concerned with the seemingly conservative reputation of Oklahoma before coming here.
Now, I’ve been studying here for half a year and I can tell you that you don’t need to worry about how the environment here responds to your queerness. Right away, I can tell you that I’ve been walking while holding hands together with my boyfriend (I am a male) all around campus and we have never encountered any unpleasant, let alone discriminatory, treatment.
Norman (the town where OU is) is known to be the most liberal place in Oklahoma because of the university. OKC, which is the biggest city nearby is also pretty liberal.
Having that said, the liberal and “pride”, sort of rainbow-ish atmosphere will not be as present as it was in New York or California, I guess. But I personally find it more comforting to be in a lukewarm setting where it’s liberal enough for me to feel safe being queer but not too liberal (in terms of LGBTQ perspective) that I almost feel like I am pushed to be loud and shouty about my queerness.
OU also has an LGBTQ lounge where you know you can always find a safe space with a small group of people. The faculties here are trained to be LGBTQ ally, and so on.
The takeaway is, you can’t really expect the kinds of hyper festive rainbow pride celebrations in OU (although you will often encounter rainbow flags here and there on random corners of the campus), but I can assure you you have nothing to worry about in terms of being queer here. It’s a friendly community.