Were you breathalyzed? Did you admit to drinking when questioned? Do you have an attorney?
A minor in consumption is a class c misdemeanor in Texas. While you cannot hurt yourself particularly by trying your own case, because the penalties are not severe, this is still a misdemeanor charge and a conviction cannot be expunged under Texas law. And even though a C misdemeanor is not reported to the state or Federal data base and so it won't appear on your criminal record, the conviction would still be a matter of public record and the files obtainable in the courthouse.
Criminal cases can have lifetime consequences. And if you cannot get this case dismissed because of any allegations on the criminal court complaint that indicate you'd actually been drinking, then if you want to go to trial, for best results you should have a lawyer representing you on the case.
Sloppy police paperwork can certainly be used to create reasonable doubt as to the police officer's capacity to accurately observe and record facts, but cross-examination is an art and the rules of evidence and their applicatio, which you won't know, may prevent you from getting out the information you need to support your theory of defense.
Additionally, if you have no criminal record, you'd likely be eligible for a diversion or deferred adjudication, which would give you a period of community supervision during which you would have to keep your nose clean, pay fines, so some community service and take an anti-alcohol class. Upon successful completion of all of that, your charges would be dismissd, and yo ucould get a certificate of non-disclosure. So you can't get this case against you dismissd outright, this may be preferable to risking trial, asi it's a guaranteed dismissal if you hold up your end of the bargain.
You may be able to talk to the DA to negotiate something like this for yourself, if you are interested. On the other hand, frequently DAs refuse to bargain with unrepresented defendants except on the record before the judge, and if that's the case, you may again find you would be better served with a lawyer, if you can't succeed at getting what you want.