Sail planes are, by their nature, easy to fly. Most thermal gliders fly themselves. Some years back, when a member of a large glider club, it was almost the norm that beginners would solo on their first day out. So don't worry about learning to fly a thermal glider. Start with a 2meter and you'll have no trouble learning to fly it.

On the other hand, you still need to find some glider flyers to learn from. The real hurdle to flying pure gliders is finding a place to fly. There aren't going to be many sites where you can launch them, and there are a few things to learn about that part of the envelope. You need to find glider flyers because pure gliders don't dovetail into power R/C very easily, if at all. Oil and water when it comes to operating the two different types at the same time.

The glider forum here at RCU would be a good place to look for help getting started.