Sad mistake. Clutch?

I drive a manual coupe cobalt
I was rolling backwards in neutral at about 20mph
I was going to put it into first and burn the tires
I accidentally hit third gear instead of first.
My car did not stall and immediately after letting off the clutch in third I re-engaged to first.

My friction zone (I think this is the term) is almost non-existent now.
I don't think it's my clutch because I have absolutely no gear slipping.
What do you think