
In the first movie, Morpheus tells Neo that they don't free a mind after a certain age. But that age is never given. However, we do have some clues to when this is.
We know that some children have already been freed as they know such things as the actual reality of the Matrix. Remember "There is no spoon"? So they can be very young. How can you determine who is to be freed at that young of an age, and why was the oracle in charge of them?
But we know that it can wait for at least the time when you are old enough to understand what is being told you. Cypher wished Morpheus would have told him more before he made the choice. How old would he have been when he was told about the Matrix? It seems like he would have been older than a child to feel that way because you couldn't have gone into great detail about the red pill with a child. And for that matter, did the freed children with the oracle also have to chose between the pills?
Konquererz you are asking many questions so I will try to sum it up here. The age at which one is freed is the age at which one can best show that they are aware something is different. I suppose it is similar to how a child says, "I see ghosts", that usually happens around 3-4 years? You also have to consider that rescuing a human is a traumatic experience and you would not want for them to be swallowed down that tube at too young an age, so maybe the age is around 8-9 when they could handle that kind of experience a bit more.
That question about Cypher is actually discussed in another Thread here, do a search for his name. As for the Oracle, who else would do it? The Oracle within the Matrix would be comparable to a fortune teller / psychic of today, and they tend to followup with people who have gifts, but that is covered more in the Oracle Thread.