Yeah, what they said. As far as a first bike goes you are going to want something smaller/lighter/less powerful. I have known many many people (men and women) get their first motorbike (usually in the 600cc range) dump it at a stop sign, wash out the front wheel, or end up very intimidated by the power and acceleration. Not to say that you would fit in the category but just some friendly insight.
I would also suggest a 250cc to start out with-all the big manufacturers make a good one and even if you get bored with it in six months it will empower you with confidence that will make it all worthwhile.
I have had an XL 650, the 650GS, an 1100GS, etc. and now I ride a KLX250SF and love it. I'm 175lbs. and 6'2" and find it to have adequate power and you can't beat the quick maneuverability.
Good luck with your choice and welcome to the two-wheeled-world!