4
Hey Sasbon
First of all - Welcome!
Default You have the 3 groups, with You selv in Webmaster-group.
A good idea is to create a Admin-group whith the same priveleges as the webmaster-group.
Create a new user for the webmaster group and change you own account to Admin-group.
If You have done that, you always have another useraccount if anything goes wrong
Just remember to permit the previleges to the admin-group every time you installe something og create new categories.
Trust mee - You well get lost of the feeling that every thing is lost.