It appears to be a rewrite of the Jesuit motto, “Give me a child until he is seven and I will show you the man”.
The “mine forever” version has been attributed to St. Ignatius as well.
Vladimir Lenin: “Give me four years to teach the children and the seed I have sown will never be uprooted.”
Adolph Hitler: “Give me a child when he's 7 and he's mine forever.”
http://hernandotoday.com/he/list/hernando-letters/letters-to-the-editor-20140105/
Thanks. Some quotes get attributed to multiple people without knowing who the true author really is.