STOOOOOOOP!!!!
fair play for having a go but be careful. You should really use a valve sleeve to stop scuffing the inside of the stem seal as you drive it down. The ridges that house the collets can cause this and make the whole job a waste of time and money.
Oh and yes a socket is the best way to do this. Allowing the top of the valve to poke out of the socket hole as you push down.