Hello Cloud Motion!
I started in Gen 3 too, but with Emerald! n_n Yeah, Alpha Sapphire is best imo. And you came to the right place! PM a mentor
here to get one to help you with the basics of battling and teambuilding skills. In addition, once you have found a tier (or two, or three) you like, you can really start to sharpen your skills. In addition, I would recommend trying each tier and their respective rooms to get a feel for them. Also, once you've made some teams, visit the Rate My Team section to get other users to help improve them! In addition, go
here to get a quick overview of how things work here. Have fun and good luck with your competitive battling!