Actually, it's pretty easy. A decent morphing software, a series of images, then you specify pair points
on each photo. As the series progresses, you see apparent aging in the subject in supposedly real time. There are some freeware applications available, you'd just have to check to see what would work for you.
I use Abrosoft's FantaMorph, but it's not cheap - $49.95 US, and I don't recall whether that was BDJ or not.
If you try it, remember that the more pair points
you set, the smoother and more realistic the transformation will appear.
A pair point
is, for instance, the tip of the nose in each image, the earlobes, the tops of the ears, the eyebrows, and the like. The more pair points you have, the smoother the transition will be.]
You can also set a reverse morph, i.e.
old maid to young girl, by changing the the photo order.
Oh, yeah, doesn't hafta be photos, can be any image set. Once changed a Mercedes into a Model T that way. Transformed from the Mercedes to a Pontiac to a Chevrolet to a Ford to a Model T, each one (1) older as the morph progressed. All the images were commercial advertisements
Edit: link for FantaMorph