You can use any water you like, really.
If you are the imaginative type you can always think of a way to make it feel special by personalising it in some way.
But the most important thing with any ritual is not what you use as your tools but the emotive force and energy you yourself put into your performance of the ritual.
Your own feelings and the emotions it produces are what is important - changing the world around you in accordance with your will.
If you wish to shave your head for the ritual there is no reason why you can't grow it back afterwards. Like any ritual, what happens in the ritual chamber is performed specifically within its confines.
Just enjoy your ritual and may it bear the fruits you desire. Good luck.
I am sure many here will look forward to reading more about you in your required introduction. I know it can seem like a pain but I am afraid the owner of this board does request that we make one. It's understandable really, with all the effort he puts into maintaining this place I can see why he doesn't want trolls coming on and mucking it up. The introduction is a good way of gaining an insight into whether a new person seems OK.
By the way, a few little mistakes only, but otherwise your English is pretty impressive.