When I first brought my Norton Commando new in 76, I was 17 years old and have only rode jap bikes before that, I picked my Norton up and when I left the shop I just got around the corner and a bus stopped in front of me, I went for the brakes and hit the gear lever instead but lucky I had quick reflexes and turned around it just missing the rear bumper, I shit myself and was a very carusous ride home after that, it took about a week to train my brain after that, so give it time to train your brain, you won't hurt the gear box, all you will do is labour the motor by going up a gear and most of your braking is done by your front brakes.
So get use to it and enjoy smooth gear changes as mine just clicks into gears, its such a sweet gear change compared to left hand changes.
Ashley