K.C.
Hi M. - I just went through this with my 16-in-June son. We had to go to Plano to "get processed" because he did a "parent taught" class. You have to get processed for the licensing exam at the same location where you got your permit. This rule seems to only apply to parent taught courses. Plano opens at 7:30 and we got there around 7. We waited in line to get in, waited in another line to get processed, and waited in a third line to set up his driving test appt. for two weeks out. We were out of there by around 10:30. Lots of lines but all the people there were nice and helpful.
They told me that since my son was processed, he could take the exam anywhere. We called around and mostly just got busy signals or no answers. I did talk to a nice lady at the Sherman office and she told me they were now scheduling two weeks out as well. So, don't go to Sherman until you call them and confirm whether they are taking walk ins.
We ending up going to the Northwest Highway location. I talked to a lady there who said they only do a certain number of tests a day (I can't remember the exact number 30-40, but fewer if they have to do a lot of 18 wheeler tests) and that summer is very busy. We got there around 6 and there was already a line. We took our folding chairs, drinks, breakfast, and books. It was no picnic but it wasn't miserable. After the line to get in and the line to get to see someone, we just barely missed the last driving appt at 9 or 9:30. So we got the first one at 10 or 10:30 (hard to remember the exact times). He took his test, passed, and we were home before 11. Fairly painless. (and yes, I did call Plano back and cancell his appt!)
In regard to the test, make sure she is good at parallel parking and that she treats stop signs as stop-stop signs. Stop behind the line, then inch forward to where she can see and stop again before going. Wish her luck from me!