It's actually a pretty good way to learn to surf. It's much easier than attempting to learn on your own by kooking around in the ocean like I did. I've surfed it a couple of times (been surfing for over 30 years) and the waves are relatively powerful, but not nearly as powerful as what an equivalently sized ocean wave can be. Plus there are lifeguards/trainers watching should anyone get in trouble.
If you do it, it WILL freak you out the very first time you're sitting in front of that concrete wall, hear the huge flushing sound, and see a mountain of water coming at you. It's a surreal experience even for seasoned surfers. You'll adapt quickly though. After the initial drop-in the wave reduces in size rather quickly and wipeouts are gentle and nothing near the washing machine type action you can get in the ocean.
One noticeable difference (at least to me) between TL and ocean surfing is the salt water vs. fresh water. Fresh water doesn't provide quite the bouyancy that salt water provides so your board doesn't sit as high in the water.
I'd also recommend you use a longboard instead of a shortboard initially. It's easier to stand up on and will help your confidence along. If you catch on quickly you can move to a shortboard later.
I'm not sure of the cost. I paid @ $120 to surf it each time with about 15 other people. We got around 25 waves each and the wave machine was ours for around 3 hours. I don't know how long the lessons last.
Good luck and have fun.
I'm concerned about how cold it will be at that hour in mid-Dec. Does anyone know if they provide wet suits?