Is this a good street bike to start with..?

I choose a yamaha r6 07. Never rode before, eager to learn. 5'2 120 lbs.... am I taking on too much?

Try different bikes, go to dealers and sit down on the different sport bikes, find the one YOU really like.

However, not to be a drag, but if you have never ridden something with two wheels and an engine before, taking a motorcycle riding course, instead of just getting your temporary permit and jumping into the street with a R-class motorcycle would be a very very good thing for you.
For myself, I drove around on a moped for 2 years, then bought a GSX-R 600 as my first real motorcycle.
Just take it EASY in the beginning, try to keep out of first gear except for getting out of intersections, get to know the bike, don't corner too fast, accelerate too fast until you have a really good feel of the bike itself. These bikes are made for racing, and they will behave like wild animals if you let them.

Conclusion, choose the bike you really want, don't let anyone else tell you different, but make sure you know how to ride, take it slow in the beginning, and most importantly, use protective gear!! Helmet is absolutely mandatory, but a jacket, boots and gloves are also things that can save you a lot of pain.. (and use jeans or riding pants, not shorts or other thin garments).

If you've never ridden, for pete's sake start on a USED conventional design then transition. You may not like the sport set up and it is definetly harder to learn on.
Used for one reason DEPRECIATION. You can find a used R6 or any thing else, maybe a year older, for a substantial savings.

I didn't start flying in a jet. Don't try to learn on an absolute rocket. Considering your size, I'd go with a Kaw 1200 but I'm an absolute madman. Considering your experience level, an older conventional 500-650.

...im just telling you from experience that that bike will be way too much and way too big for someone of your stature and experience to handle.. go for a ninja 250 or something like that...you need to be sure you can touch both feet flat on the ground when on the bike.

NO GOOD. You will kill yourself on a r6 if you never rode before. Start out smaller and not so new. Why waste money? Chances are that you might drop it. Most new riders do. Take a riding course too.

Add my post to the chorus.
Buy something smaller and cheaper. In the event you drop it, you will be out a lot less money.

Start on a CBR 600 RR. a used one. much more forgiving.

NO way.

start with vespa et4

ya start out smaller