Car accident help!!!!?

me and my friend were driving down my driveway which is hard to leave out of. i stopped and hye stopped close. and then i went half way into the road and a woman came down at 60 m/h. i backed up and when i went out half way he followed too closely. then whn i backed up i hit him . whos fault is it and is there a law about distance when driving. i backed up to save my life