Indoor or outdoor wedding? If it's indoors, there's no reason to wear a light-colored cotton suit. You'd look better in something darker with a white shirt & nice tie. But if it's outdoors, by all means carry on with the khaki suit & pale blue shirt, no tie.
As for the boots, all I can say is that I've lived in Texas on & off since 1985, and I have never once worn boots with a suit.