Gliding looks fun but not too sure about the thermals. No engine either.
Last time I saw a glider prang, it was
because the glider had an engine. The blasted thing wouldn't start and then the workload in the circuit became too high. No major harm done, though.
Thermals are fine and fun - just look for a circling aircraft or buzzard, then go and play with them.
In a strong thermal with another glider at the same altitude, you check where it is by looking upward to see the top of the pilots' head (well probably his beany hat, actually) because you're both at 70 degrees from the horizontal. If you get too close to the buzzard, it'll show you its talons.