Giday mate and welcome to the CBRF
I am, a little different in opinion as far as which ride you should choose..
I personally started on a 900 at 17 and sure it was a huge learning curve.
I think buying a bigger ride first up is not so bad a choice at all.....as long as you do not spend much on buying her .. and have a very good understanding of what WILL happen if you get on a big ride and try to go boy racer riding too soon..
As mentioned , the earlier 600's are very inexpensive to buy and I also agree that they look better than some of the newer ones..
Better to throw a cheap ride down the road and learn without financial pain as well :-)

It is pretty normal for us older experienced riders to lecture about the danger of new young riders buying big first rides mate , bit I still maintain that the bike, regardless of power is only as dangerous as the bloody riider on her !! ...

Anyway mate ...good luck with what ever you buy and just remember to take care and understand well that the ground and cars hurt like **** when you land on them or run into them ...