Matthew 18:10 does not necessarily mean that each child has an angel.
"See that you do not despise one of these little ones, for I say to you that their angels in
heaven continually see the face of My Father who is in heaven." (Matt 18:10)
Some have interpreted the angel, mentioned in Acts 12:15, as caring for Peter at that particular moment.
"When she recognized Peter’s voice, because of her joy she did not open the gate, but ran in
and announced that Peter was standing in front of the gate. They said to her, 'You are out of your mind!' But
she kept insisting that it was so. They kept saying, 'It is his angel.' But Peter continued knocking; and when
they had opened the door, they saw him and were amazed." (Acts 12:14-16)