Here's a great verse.
Luke 18:15-17 And they also brought infants to Him, that He might touch them. But when the disciples saw, they rebuked them. But Jesus called them and said, Allow the little children to come to Me, and forbid them not. For of such is the kingdom of God. Truly I say to you, Whoever shall not receive the kingdom of God as a little child shall in no way enter into it.
Understand I'm not trying to say that we can only become Christians when we are young, but we can only become Christians when we hear and accept God's word with the same innocent trust and faith as many children have. A faith and hope that has not yet been proven wrong or dissillusioned by defeat. And when is a person most like a child in their innocent acceptance than when a person is a child?
This is definately the time to influence them. God's message is always profittable. There is never a losing situation. You alway plant a seed.
Isaiah 55:9-11 For as the heavens are higher than the earth, so are My ways higher than your ways, and My thoughts than your thoughts. For as the rain comes down, and the snow from the heavens, and does not return there, but waters the earth, and makes it bring out and bud, and give seed to the sower and bread to the eater; so shall My Word be, which goes out of My mouth; it shall not return to Me void, but it shall accomplish what I please, and it shall certainly do what I sent it to do.
Proverbs 22:6 Train up a child in the way he should go; and when he is old, he will not depart from it.