There's no real "certification" process in Texas. You just sign up with a chapter, pay your dues, get assignments, then work your way up. You will have the opportunity to attend camps and get better.
Since you are in Deer Park, go to this site and if you haven't already, sign up:
http://www.houstonref.com/houstonref.php. There's a chance they aren't checking this stuff right now since they are busy with end of the season stuff.
If you don't hear anything in a week or so, I'd contact Ben Frank at
[email protected] if you haven't already. He's listed as the secretary of the Houston chapter. I'd make the effort to contact him soon as the deadline for paying dues for returning members for next year is soon (usually March 1 or 15). You're not a returning member, but there could be an advantage to signing up anyway.
Otherwise, you can find out when the first meeting is next fall.