Hi Debbie! welcome to ATP!
1. My theory is a little backwards: first and foremost, grow what you like to eat!
Just bear in mind that FRESH veggies chosen for quality, will be MUCH better than supermarket anythings. If you were never fond of snap peas, snow peas, spinach, lettuce or cherry tomatoes, the ones you pick and eat within a few minutes might rapidly become your NEW favorite vegetable.
2.
I also don't bother growing what I can buy cheaply, like carrots or potatoes. But some people do, so maybe fresh tiny carrots have virtues I don't know about.
3.
Whatever you plant your first year, your biggest harvest will be new gardening expertise. I was getting disappointed after a year or two when I kept killing plants, until someone straightened me out: if some gardener isn't killing at least SOME plants, they aren't stretching themselves enough. Learning only occurs when you're a little too ambitious and find out what does NOT work in certain circumstances. Then you can go to forums like this and ANSWER questions instead of ask them!
So try things you like, and FIND OUT how easy they are for you to grow. Some things that everyone else thinks are fussy, impossible plants will turn out to love your methods and grow like Jack's beanpole for you.
Be sure to pick at least 2-3 things that "everyone says" are incredibly easy to grow and 100% foolproof. If you're like every other gardener ever born, half of those will spite you by dying in droves - just to mess with your head!
I see this especially when starting seeds indoors. The seeds that I expect to germinate 90%+, I sow thinly. They typically get fussy and only a few come up. The seeds that I expect to be difficult and have low germination rates seem to put up 150% or 200% as many seedlings as I had seeds ... playful little beggars!
4. Maybe the conventional wisdom is to grow things that like your climate and soil. It makes sense, anyway.
In Texas, I guess that means that they can grow in sandy soil and take intense heat and little rain without burning up, for a summer crop. Hopefully some Texans here can suggest what those are. Beans? Eggplant? Okra? Chinese long beans?
Just beware: people in cooler climates will tell you that "tomatoes and peppers love heat". Well, that's only true up to a point. In at least some parts of Texas, their "spring tomatoes" are stomped on by the summer heat like Bambi being stomped by Godzilla. They have to start more tomato plants for the fall crop.
OR else plant things grow fast enough that you can have a Spring crop and a Fall crop. For example:
lettuce
spinach
chard
snow peas, snap peas, other peas
Bok Choy (and Chinese cabbage in the fall)
radishes
You could plant some garlic cloves now for spring harvest.