more to the point, why are you looking at getting a road bike if you are 15? you will not be able to ride it anywhere legally, and if you reckon you're getting an R1 at 15, unless you race on bitumen competitively, i'd say you may be a little full of shit... regardless of your height, a 15 year old on an R1 is probably going to be a dead 15 yr old on an R1 pretty quickly... and as you mentioned, you're moving up from a 125cc fourstroke.... so the squillion horsepower step up to an R1 is probably going to increase your pucker factor by a fair bit... more to the point, where the hell does a 15 yr old get a lazy 10-15K to buy an R1 anyway, unless they move "recreational" drugs around a bit????
At the end of the day, you arent legal to ride a road bike on anything less than closed course tracks... and if all you've ridden is a 125cc fourstroke pit bike, then an R1 is probably going to kill you before you hit the end of the driveway... which will be the limit of the area in which you can legally ride it anyway... Regardless of the state you live in, you will not be legally licensed to ride an R1 until you are AT LEAST 19 and on a full license...
So you will have an R1 sitting in the shed for 4 years until you can ride it...
I've come to the conclusion sir, that either you are rather inexperienced, in which case fair enough, and suggest that you buy something like a 250cc trailbike to ride on closed (read PRIVATE PROPERTY) tracks until you are legal to ride on the roads, or B: you are entirely full of shit....
Which one, will depend on your reply...