If the OP has read this far, he'll see plenty of well thought-out posts, pros and cons, even recommendations. RB's, 4x5, etc.
And with respect to all of those valid comments, I'll add: you never know until you try.
There's something that still, to this day, makes me go "ahhhh" when I frame up my first shot in an RB shooting session. That big-ass, bright viewfinder, it's like seeing an Imax film after watching TV. Something in how color and DOF renders while framing, it still brings back the first day I opened a KEH box and looked through my first MF viewfinder. The chunky clunky body, the wind-it-twice process… all of that effects the way I shoot and the way I feel about shooting those particular moments.
It's really not just about the neg size (though the neg size on a light table is still, after a couple decades, kinda thrilling to me for roll film). So much of this game is your connection to the gear, are you a "the gear just disappears when I shoot" type or "I have to fight with the gear but it's like fighting with a hot woman"?? Only you can answer that, but… if you find you're drifting off to sleep dreaming of RZ's… get your hands on one and see. Photography and gear isn't like American marriage - it's like french dudes with three mistresses and a wife. You can love them all. (This reply is getting non-PC and sexist, ain't it??)
That said, on a high school budget - I'd look hard at an RB Pro-S setup - you can go much cheaper than RZ and your negs will be the same (other than any RB vs. RZ desire issues, see above paragraphs where logic isn't the only factor).
And a high school shooter wanting to add 6x7 to his 645? Respect, man. There's hope for the planet after all!!!