I think you can go straight to road bike, I'm about your weight and ride one. I'm still working out a numb hands issue but it's getting better as I find better way to position my hands and let the weight out of it.
My only recommendation would be to go with the endurance models instead of racy ones... will make no difference whatsoever in terms of performance but you might get a ride position that's easier on your back.
or may be it's just gimmick, who knows... just test ride them all and see which one feels better