Depending on how she is as a person, this may or may not be something to consider...
Set up a mailserver for her and your wife. You may very well have your own domain and mail already. But just ask some friends to help to ensure this will last a long time.
Then I'd suggest a series of short messages as well that could go on a very long time. Video, yes, by all means. But even some emails. Start writing down stuff now as it comes to you. The first time you remember getting in trouble. The first time you had chocolate. Or the first time you had a drink of alcohol. Anything. Everything that sticks out to you as a story. Don't preach. Don't try to impart anything. Just be you in your own voice. Talk to her like you would anyone you love. She'll find wisdom and encouragement in those things. We are only the stories we tell. Facts can be found anywhere. Information is handed out freely. But it's the connections we share with the people we love that give meaning to all of it. Give her the chance to have your stories unfold like they naturally would. Who knows what she'll be doing at 30 when that email finds her. Personally I'd laugh, cry, and be happy to have another tale from my father.