I'm not going to tell you what to ride, but I will tell you that the Busa is just about the worst learner's bike I can think of.
If you buy something like a 500/600, it will be lighter and much easier to handle at low speeds, plus much cheaper to buy, and /or repair. You can learn cornering techniques, and how to use power in corners without having a sudden surge of power push you off the road.
In six months, you could become a competent rider with the smaller bike. In six months with the Busa, you will still be a beginner searching for the skills you should have already learned. In six months you will be faster on the smaller bike, unless it is in a straight line.
Get into a turn with a CBR 600 in a lower gear and you can learn how to use the throttle to balance the bike and shoot out onto the straightaway. Not very difficult.
Try the same thing on the Busa, and you will either go very slow to avoid the power surge, or you will be in danger of losing it, since you will not have learned what a bike feels like as it approaches the limits. The Busa gets to those limits much quicker than the smaller bikes, thus is much harder to ride at speed in turns.
If you start out on the Busa, you will be a slow rider on a fast bike for a long time, if you survive. By starting on a smaller bike, you will gradually become better than the bike, and have a much better chance of survival. At that time, it is time to upgrade to something like the Busa.
Starting out on the Busa is not impossible. Others have done it,and some have even survived, but it's more difficult than necessary.
It is a lot like deciding that you want to learn to fly, and asking if you should buy a Concorde? Exactly the same concept, and just about as sensible.