For a first bike you’ll keep for at most a year, that’s a great deal, even if the ergos aren’t perfect.
I’m 6′, 200 lbs and have been riding a Buell Blast for a year. It’s kinda small for me (all Buells are snubnosed bikes to begin with)…the seat height is 27″, and my knees are high on the tank. But it’s worked out just fine, and if I had to do it all over again, I’d get the same bike.
The Rebel’s seat height is about the same, so it should definitely be do-able for you. And as others have pointed out, the market for beginner bikes is so strong that you’ll easily get most if not all of your money back. Think of it as just a rental bike!