Gliding is a great and relatively benign training environment. If you get any private powered training, you run the risk of learning in a non-standard (ie not Military) way that will have to be "unlearnt" during your training. This will add time and stress where you will have little of one, and plenty of the other already. As already stated, gliding will teach you some solid fundamentals and some Airmanship, plus you will be over the "wow" factor of being in the cockpit and can concentrate more on the lessons. Well done, remember to enjoy it!!!