I would recommend the FFXI subreddit. They're super helpful there

I think XI is a great game, and can be a lot of fun, even at this point in its life. Fair warning - I think it's a game that you really want to have to play as the first week or two will be quite trying. You get dropped into the game, no gil, no quest icons, no idea how to even open the bloody menus (which you will use extensively - but if you can survive the learning pains, it's a great game.

Not trying to scare you off here, I just think coming from modern games and then going to XI can be a bit of a shock X: Still totally worth it!

As Urthdigger mentioned, Asura is I believe the most populated shell there. There's a nice LS (FC equivalent) named Asatru that is quite friendly and takes all types of new/returning/experienced players just looking for a good time. May want to look them up.

And again, FFXI subreddit! Quite a lot of information there and guides, how to start, what to do, external references, etc. Good luck