While taking the class after a conviction is often mandatory, there can be advantages to taking it beforehand.
There are three things you have to do if you are on probation for a DWI in Texas, in addition to whatever else the judge decides to add:
You have to take a DWI education class.
You have to get a substance abuse evaluation done.
You have to attend a Mothers Against Drunk Driving victim impact panel.
In every DWI case, I meet with you to go over the evidence and we determine together if this is a case that we want to fight at trial, or if it is a case where our goal is to work out the most favorable deal with the shortest probation. If we decide to try to negotiate a favorable probation deal, you may very well want to get those three obligations out of the way early on.
Not only does this expedite the process, it shows that you are being proactive and will help us negotiate a shorter term of probation or lower fines.