Welcome back fellow Meteor Survivor! (and Balmungian )

ARR differs in a lot of ways from how 1.0 played, but there are still a lot of similarities that you should be able to get back into the saddle fairly quickly (being a 1.0 player you get to start with all your previous EXP, gear and levels intact ). One thing about ARR though, is that things are designed to be unlocked gradually as you play through the main scenario (quests identified by the Meteor logo), however, as a 1.0 player you get to start the game with many of these things already unlocked, like you can switch classes to any you unlocked in 1.0, you can ride a chocobo at the start (if you had one in 1.0), you can rehire your old retainer, and much more. So 1.0 players are special.

As Tyr said above though, the important thing is to have fun!