Congratulations bro! Congrats on taking the first step towards being completely addicted to a fantastic new world. You'll soon be waking in the middle of the night to write out a new transition or technique. That's the new jiu jitsu dope and Zog is your pusher ;-) lol.
personally i hate mouthpieces and cups I feel like they weigh me down. who knows maybe that will make me toothless and impotent in the future. but hey like my dad always said nutshots build character
I've found shock doctor jock and cup to be the best so far. Had no probs at all with em. I wear a custom fit mouthpiece so obviously recommend one of those. Other than that shorts and a rash guard is all I can think of as necessary.
I recently started JJ so I was in your shoes 3 weeks ago. Go in with an open mind, and be fearless. Regardless of age or size don't think too much. Also be ready to work. Enjoy meng, I'm having a blast.