I'm 6'2" and well over 200 pounds... I took the cbr 125 for a test ride with a honda test ride, the bike is really good if you keep it in the high revs, (it has a rev limiter so it's hard to blow the engine). Going up a hill I almost came to a stop, the bike doesn't have enough power for guys like us. Your gonna look like a bear on a tricycle if you get that bike. Go do the test rides, you will see what I'm talking about.
Get a used bike (250cc or higher), your going to drop it, I did.
If you get a 150cc your going to be really ****** after a week of riding wanting more power.
p.s. maybe do a t-max to start? (cheaper on insurance due to no clutch). It's a 500cc! you might pay the same as a smaller clutch bike.
http://www.yamaha-motor.com/sport/products/modelhome/607/home.aspx