It will depend on the court, your performance since placed on probation, how long you've been on probation and the new charges. Obviously you need an attorney to try and win on the PI and paraphanelia charges, but even if you win, a motion to revoke based on those offenses can still be raised. You need an attorney if they file a motion to revoke as well. Many times first offenses such as Class C misdemeanors will not result in a MTR however because your original charge was so serious and drug related and one of your new charges is drug related the court might see your actions as disrespectful to the agreement you made. You need to figure out a way to show the court you're doing exactly what you're supposed to be doing and not breaking the agreement/law.
On a personal note, you're under 21 and are on probation (straight or deferred doesn't really matter) for an extremely serious offense. You could have (and maybe still could) ended up in prison for up to 99 years. This probation is a second-chance to make something of yourself and being a UT student with a 3.0 GPA etc is not going to be enough to save you if you don;t show the court you care enough to save yourself.
Although my intent in answering this question is to aid you in the legal process, my answer does not establish an attorney-client relationship in any way. You should seek the advice and counsel of a qualified attorney in your community to evaluate your legal needs and to advise you. No Attorney-Client Relationship is created without the specific intent of both parties.
The answer to your question depends largely on the judge and probation officer handling your case. If the judge who placed you on probation is one of the district judges in Travis county, it is unlikely that you will be revoked and sent to prison for these offenses. However, I would not be surprised if you had to do some jail time and an increased level of drug/alcohol counseling if you want to stay on probation.
Usually the probation department will schedule a review hearing with a probation supervisor when a probationer has some minor violations like these. At the hearing they would probably offer you some increased drug treatment which sounds like a good idea. Your probation officer will tell you whether they will go this route or refer the case to the judge.
Be sure that you continue to do all the required probation conditions so that you don't give them a reason to revoke your probation. It is very common for people to get scared because of a minor violation and then to stop reporting to probation. Not reporting will get you revoked, minor technical violations will not.
As you are aware, your probation could be revoked for any violation - and obviously you have committed several violations of your probation. You committed the offense of being a minor in possession of alcohol, but you also committed the probation violation of possessing alcohol (and if you were drinking, that is yet again another violation.) And you committed the offense of being in possession of drug paraphenalia which also suggests that you were probably using drugs.
You need a local lawyer how knows the judge and prosecutors to get a better idea of what may happen. This will depend not only on these people but also on the length of time you have been on probation, the facts of the original case, whether you are otherwise in compliance with your probation, and how well you have been doing. I'm going to make suggestions, but those suggestions should be discussed with your lawyer and your lawyer should make the decision on what you should do.
I suggest you start attending NA immediately and daily. While your original offense may or may not suggest you use drugs, your behavior while on probation suggests that you do have a substance abuse problem. What person on deferred for a first degree felony would take a chance on getting life in prison by possessing alcohol and paraphenalia unless they had a substance abuse problem?
You might also have a psychological evaluation done. If you do this, you must do it through your lawyer so that the person is covered by the attorney client privilege. On occasion, information gleened from an evaluation helps explain behaviors and suggests ways of dealing with problems. (Other times, it suggests that the offender has a bad attitude - thinks they are above it all, authority rebellious, etc. - that will not help and you would not want that to get back to the DA or judge.)
Frankly, my guess is that you may well be headed towards in-patient rehab. If your lawyer thinks that might happen, and if you have healthy insurance, you might have an evaluation done to see if they would suggest out-patient treatment and they would pay for it. This MIGHT avoid in-patient treatment requirement.
In my opinion, this is a very serious situation. You need to hire a very good lawyer to give you advice - that you may not like but better follow before you end up in prison - if that can be avoided.
Although I have answered the question to try to help you, you should consult with a lawyer in your area in person on the matter. In addition, my answer does not establish an attorney-client relationship between us.