well, im sixteen. I have always been the fastest on my sports teams but never decided to do track so its not like i have never trained before just not for track. As far as the accuracy of the timing i had a guy by the line saying set and then clapping, and lowering his arm as he clapped, and the guy at the finish line started timing.
Still, I ran an 11.1 on grass handtimed under those conditions when I was 13 and I run 11.5 electronic now. Hand timed is so unreliable it's useless.