Hi there, fellow Dark-Type fan! It's a pleasure to meet ya here. :) *shakes hand*
We defo have a Challenge section, where you can go ahead and take a couple challenges here and there. There's the famous Nuzlocke, the Monotype, the Solo, and even some of the most interesting challenges. You can also create your own challenge if you like! There's a lot for you to choose from, so choose wisely and you'll be on your way! :)
Yep, we're a great community, and we don't bite, really. xD Yes, you should play Gen 5. It's a really amazing generation. Not rushing you though. ;) But anyways, great to see ya here! You can always PM me if you have any questions and I'll be sure to respond asap! have fun @ the challenges section~