Adults are supposed to become like little children... so why do we decide to hinder little children?
And does God choose us, or was it only the Twelve Disciples that God chose?
The Holy Spirit can enter someone at any time. Again, when did Jesus ever say "do not baptize infants"?
In fact, Jesus' only command on baptism was to go and baptize all nations -- no age requirement... and no understanding level required, as let's face it, most adults don't understand what happens at Baptism (some more than others, but most not completely)
Can but won't, most likely... or perhaps the Holy Spirit doesn't want to. Remember... it was only at God's call that Satan took everything from Job.
I doubt it, since the Holy Spirit doesn't want to lie.
So anyway, you show me Scriptural proof where you must be a certain age or at a certain level of understanding and able to voice that understanding to be saved. Because the Gospels I read all show a Jesus who chooses us, and then we follow, and we can turn away later if we so choose to, but it is still Jesus who initiates, and we don't start it out by running to him... he runs to us.
EDIT: I am talking about Baptism of the Holy Spirit. I believe the Spirit CAN use water, but is not limited to water. Of course, the words "This is my Son, in whom I am well pleased" are uttered when? At Jesus' Baptism... Maybe before, I admit to having a less than photographic memory, but I don't recall those words being said before Jesus' Baptism in the Jordan River.