You need to find someone who knows how to kickstart a vintage bike and ask nicely if they will teach you.
If the 'bigger' people are 'slap kicking it, it will damage the starter mechanism.
It should be possible to 'feel' for compression, , let it slowly go passed top dead center and 'launch' onto kickstart at around 9~10 o'clock position.
If you cycle (as implied by avatar) you shouldn't have any problems
I rode one for a few months, never had any problems starting and I was only about 9~10 stone at the time (135~140 lbs, ~68Kg)
My girlfriend had problems, but she was only about 5ft 5", 110lbs
It's all in the technique
Oh, and BTW,you can't fit electric start to one without a LOT of work