Hi Marta! Glad you made the switch
I would suggest to stray away from rooting since you are a new user and is typically for more advanced users. Plus you can still get a lot out of your device without rooting it.
As for your music situation I would suggest looking into either Double twist or iSyncr. They both work on Mac to android for music transfer and work pretty well with iTunes. Usually all you have to do is install the application on both your Android device and your Mac.
Hope this helps and if you have anymore questions feel free to ask