I'll second all the cautious advice and also that about getting a "learner" bike, you're going to drop it at some point, probably slow speed, maybe when you hit the steering stops or something inane like that in a parking lot....DO THIS ON A CHEAP BIKE something with no body work/plastic...Suzuki GS500, Kaw EX 500, etc...maybe an SV 650 Suzuki-that bike you might never outgrow...but take a course or go to a roadracing school even if you never race...learn
how to really control the bike, you can get yourself out of or create a more favorable outcome if you know what to do when the time comes..
I have ridden streetbikes(currently have 8 bikes), road raced, been a bicycle courier(D.C. and PDX), raced ALL types of bicycles and generally spent alot of time on two wheels in traffic, a pack of 100 other riders, rubbin elbows into a turn at 100+...blah blah blah...I rarely ride on the street anymore, the track saw to that...
Once you go track you can't go back..
Remember a few things:
No body sees you
Everbody is trying to kill you
Keep your head on a swivel
ANTICIPATE!!!!!!!!!!!!!!!! probably the most important thing in traffic/close quarters racing
My friend once told me about motorcycles and licenses and being a teenager...you have the bike and the license, One of them has to go..
...Needless to say I kept the bike...
Rubber side down