There isn't really a set age. It would mostly depend on how comfortable a child feels going to the bathroom without a parent, how comfortable their parents feel about the child being in the restroom alone, and, of course, how well the child is able to use a toilet by themselves.
Rule of thumb: Until the child is physically big enough to use the facility unaided and speak in complete sentences. This usually happens around age 5 or 6. However, it's a good idea for someone of the same sex as the child to escort her or him until they're old enough to understand "bad touching" and deal with it.
In California, there is no specific minimum age requirement to be a legal parent. However, individuals under 18 may need parental consent or a court order to establish certain parental rights.
do u have to pay child support when the child is still in school at the age of 18
Even so, the child is still a minor and you are responsible for her until she is of age.
Yes, but generally not past age 23.
Until the child has reached age of majority in their state, usually 18.
Child support continues as long as the child is still a dependent; this includes school and university, regardless of age.
see link below
no 21 is the cut off age
this depends on what country, in most it is 12
until age 19
Yes, until age 18.
Until age 21, which is the age of majority in the state. see links