I just moved to CC from San Antonio. Sorry to say Corpus Christi doesn't have much to offer to a nationally competitive player.
Splatter Action Paintball just outside town has some fun rec fields and quite a bit of regular players - but no national teams or regulation field. PB FIXX is in Robstown (about a 30 minute drive). There's definitely better players at FIXX, but the field itself needs some work before it'll be on par with fields in San Antonio or Houston.
Bottom line is, if you're looking to play national paintball, you need to be traveling to San Antonio or Houston to practice. There are a few of us in the South Texas area that do it. Driving from CC to SA takes about two and a half hours; to Houston, three and a half.
The third option would be traveling to McAllen (two and half hours), which has some beautiful regulation fields and good players. But if you're going to drive that far, might as well go to SA.