of course you're not too fat to ride a bike. I started out riding on a folding bike with 20" wheels. I always imagined I looked sort of like one of those circus bears on a tiny bike.
I still rode, and kinda learned to to not worry about how I must look riding my bike, I was just having too much fun.
I would probably have a problem with shifters in that position. I have a handlebar bag that faces toward me- it's small, only big enough for a cell phone and a can of pepper spray. I still hit that thing getting on and off. Maybe the bike shop could move the shifters?
vickie