Just to expand on the lack of specified hours to "qualify". There are a range of "qualifications":
1. Flying solo. This is whenever the instructor thinks you are ready. Power experience might make this quite soon, if you're a good handling pilot.
2. Bronze. There is a requirement of 10 hrs solo or 25 launches (from memory, these numbers might be slightly off), followed by a fairly simple exam and a general flying test which will include launch failures and (from 12 year old memory) a simulated field landing. This is often thought to be the licence equivalent, though it's still very early days.
3. XC endorsement. Field selection training, usually in a motor glider (to allow go-rounds), navigation training (usually the same flight). After this you can fly out of gliding range.
4. Silver: 5hr flight, 1,000m height gain, 50km cross-country flight. With Silver, you're usually accepted as competent at other clubs, though you're likely to be made to take a check flight if you fly somewhere new or want to fly that club's gliders.
5. Gold, Diamonds: for 300km/500km flights, 3,000m/5,000m height gains. These are cumulative.
I'm part way through 5 after 12 years, and soon might rate myself as generally competent.