If you think you can control yourself, get what you want. I started on an 07 R1, I really wouldn't recommend it unless you have some substantial experience on 2 wheels else where. I spent some good time on a dirtbike, and not just cruising in a neighborhood, but ragging on it in the trails, experiencing the front wash out, experiencing the rear slide everywhere.
You know how you see those videos of people getting on a bike and they take off like a rocket, swerve, and hit a tree or parked car? That's because they don't realize that even on a 600, a twist of only a few degrees on the throttle will instantly bring the bike to RPMs that most cars don't even go to.
Respect it, don't show boat, learn slow and with people that know what they're doing. If you're going to ride with people that have crashed multiple times and they're the same ones saying that you'll be fine on a 1000, I wouldn't call them friends. A 1000 makes so much power it's absolutely overkill 99% of the time. If it doesn't scare you then it's going to bite your head off. Hope that helps.