A glider license can be earned using one of three launches: a ground launch,
aero launch or self launch. Once you get the license, you must get get
logbook endorsements for either of the others.

I am not sure there is an advantage to obtaining either the sport license or
the glider license first. Do whatever is most convenient. Both are fun and
require and hone different skills. Soaring is best in the summer,
generally, while flying power planes works well when there is no thermals.
So, I suppose I would fly with an engine in the winter and fly gliders in
the summer.

Hard to go wrong with either one.

Colin