Welcome to Argent Dawn! Along with Acrona’s compendium that Lintian linked, I’d also recommend the upcoming Arcanist Forum next weekend that Acrona is hosting if you’re itching to dip your toes into mage-themed RP with a focus on discussion. It can be a good place to learn, flesh out your character, and build connections with other mage characters if you RP one yourself.
It can be daunting to get into a whole new community without any of your past connections, but we’ve all been there at some point. People on Argent Dawn are generally helpful enough when you let them know ahead of time so they know to accommodate you!