Considering that Lane Kiffin offered a scholarship to a 13-year-old, I'm quite confident that age is irrelevant in that regard.
Someone who knows more about the particulars than me can expand further, but I assume recruiting rules are the same regardless of age, except for in-home and campus visits. I don't think those can be done until the prospect's senior year. Tommy Olson accepted a scholarship from Brewster when he was a sophomore, and met with him in-home, but the latter was incidental to the recruitment of his older brother Eddie, Jr., so I assume the contact rules did not apply in that case.