sum1

In the Annotated Screenplays it says that during the making of ROTJ Anakin was envisioned as being in his 60s in ROTJ. That puts him in his 40s when Luke and Leia were born.

I always imagined Anakin went dark the same way Luke nearly did in ROTJ -Palpatine got him hopped up on rage and hatred and he went over the edge.