Welcome to Android. As you are new, my advise would be to just use the stock for some time and get a hang of android in first place. When it comes to rooting, it would say do not do this as, you are very new to android. You might end up messing the device itself. Rotting gives you lot of control over the phone and it allows many useful apps to be used which otherwise is not possible with stock. To name a few, Titanium Backup, this is a very powerful backup application for phone and this comes in very handy when lets say, you have issues with your phone and you want to do a factory reset. Rather than installing every application from scratch, you can have titanium do this for you and most importantly it can restore data too, i mean, like lets say you have played a game to certain level and you have to format your phone, in that case you restore that game to as it was just before formatting.
Also since you are new, i would strongly recommend not to use any custom ROM. This is purely until you get an hang of how android phone works.
I have one thing to says, by switching to android, now your phone is truly yours , not just controlled by the phone manufacturer.