RE: Sighting "in" at 25yds, Where is it at 100yds?
Ok, I'm really going to sound mean here, but truth be told, I usually am mean....Shooting your gun and sighting in at 25yrds thinking it will be then sighted at 100yrds is just stupid...there are hundreds if not thousands of these idiotic charts running around even in our "modern age of enlightenment", they are a starting off point only, basically so you can take a freshly boresighted rifle to the range, shoot at a target say 14" square at 25yrds (which would be 56MOA, easier to hit than 14MOA), get your shots on the page to the point you'll know they'll be on paper when you push things back to 100yrds.
You also didn't say what cartridge/bullet weight/bbl length/muzzle velocity/balistic coefficient you'll be shooting, I can sight in a .22lr to shoot one ragged hole at 25yrds, that doesn't mean it will be on at all at 100yrds, nor is it necessarily true for a .30-06.
You live in TX, there are rifle ranges all over in TX, my advice is get your rifle "rough sighted" on your 50yrd range then head out to a 100yrd+ range.
The only real way to know where your rifle/load is going to hit at 100yrds is to shoot at 100yrds.