Kids blame their parents. You don't have to have raised them in a cult for them to blame you for how their lives turned out. This is actually a stage of development that people go through. A lot of children (meaning offspring... not meaning young in chronological age) go through this stage in their early 20's. Some people don't go through this stage until they are older or also going through a mid-life crisis. Children in crisis often blame their parents.
You can empathize with your children. You can have regrets. But at a certain point in time you need to let them know that blaming you isn't healthy and they need to get on with their lives and more forward or they need professional help. They might need both.
You did the best that you could. You got out. That you didn't get out in time... well you can't change that. And who knows if that would even have been better for them? Playing the 'what-if' game is never a good idea.
The real danger is letting your kids think that it is okay to play into an idea that their lives would be drastically different if things had been different. Very little in life changes our course and destination. We have all these movies telling us that if we made just one single change in our past our lives would turn out drastically different but I don't believe that is true. The only changes that massively effect our lives are the pivotal choices. You already did that for them by deciding to leave. That was a pivotal choice. When that choice happened wouldn't have made as big an impact as the fact that you did leave.
Don't be too hard on yourself and don't let your children be too hard on you either... unless you did something really wrong to them. Waiting to make sure you are making the right choice isn't the wrong choice to make.