[The Deuce]

First of all, I would double check the laws on purchasing without a license. I bought my first car without one, so it would seem bikes may be the same.
I know what you mean about getting parents approval. Luckily my dad has owned bikes since I was a baby, so my mom was pretty much used to the idea of them being around. I just paid my insurance, $275 for full coverage and a $400 deductable. I am a 23 year old male and I totalled my last bike about two years ago. My mom almost puiked when she heard, and I told her after WALKING in the front door of her house.
Which brings me to my next point. Get leather! I was riding on the 405 and wasn't paying attention. Went highside and bent my frame, but rode it 60 miles home. I melted the side of my boot and glove, but my jaket doesn't have a noticable mark. I recomend you buy a new helmet (what is more important than your head?) and make sure it is SNELL and DOT approved. If you pay more than $300 it is for looks and other stuff, not keeping your brains in.
Get yourself into a saftey course. A friend of mine teaches a motocross one down here, and the one I took has saved my life a number of times. Not that I am such a bad rider, but people in cars are stupid.
Lastly, take a good look at your legs and spinemup's post. I don't mean to scare you, but riding is not a question of IF you crash, but WHEN. There are things you can do to be safer (like yeilding to law enforcement) but there are inherent risks.
Let us know if it is a katana (gsx) or a gsx-r. I hope you have as much fun riding as we all do.