I think there are three types of strategies to this. 1. Get a few sets under your belt before going to ski school so you have some muscle memory. Think more of “awaken those unused muscles”. 2. Go “cold” and establish a good baseline of coaching. Your first two passes may be a bust, but your muscle memory will kick in fairly quickly and you’ll feel more comfortable on the third pass. Then the coaching you receive becomes the foundation of your skiing for the rest of the season. 3. Skiing for two to three weeks before you get coaching. This option, while helping you get in ski shape may hinder your ability to apply the coaching you get because you have engrained your muscle memory to your “old” habits.
Depending on how good of shape you are in before you ski should help you determine how sore you will be. If you are in good shape, make sure you get in pull-up shape to help your hands and lat muscles. (This has greatly helped me). Bring a roller and do a lot of stretching before/after you ski and that will greatly reduce your soreness.
As with every opinion/option you know “you” best. No matter what, some coaching is well worth the money and will pay dividends to your skiing this season.