I am not a doctor, but I think it would be dangerous for you to experience another vaginal childbirth while you have a cystocele.
The very best thing would have been if you had been using the Kegelmaster BEFORE you ever had your first baby, but it is even MORE important that you get started before your cystocele becomes worse.
It is definitely not too late! If you have been breastfeeding the kids that would help explain the cystocele. A low estrogen level has definitely been associated with cystocele and breastfeeding lowers estrogen.
You'll find the Kegelmaster does not constitute a huge interruption in your daily lifestyle, but it is one of the most important things you can do right now - under ANY circumstances.
I wish you the best.