When you are learning new things time is never wasted. So I would say it’s definitely worth the time.
If you want to be able to write games for any platform then OpenGL is probably one of the most important APIs to learn.
As for how long it will take… Well you can learn the basics of OpenGL in a day or two by reading books like The Red Book and The Orange Book.
But to master OpenGL (or any complex API) it can take many months or years.
If you are lucky enough to be in a country where the game industry is just starting then you have a wonderful opportunity… So I would say go for it for that reason alone.
Perhaps start checking out web sites like Gamasutra.com also… There you can read an awful lot of relevant industry news, and read blogs and articles from all levels of the industry globally and learn a lot.
Good luck… and have fun.