That is what i'm like. There is a wall near me, about 3ish pallets. I was backwheeling it fine one day.
The next day I went and tried it again and my foot slipped off the pedal I fell backwards and smacked my back on the wall (Y)
This was about 2 months ago now, i've still not tried backwheeling it :D
I think I just need to work up my confidence again.
I'm sure you'll be doing it soon :D Good luck :o