You need to discuss your previous birth with your OB or midwife in order to get a clear view if you would be a good VBAC candidate. You also should do your own research regarding your situation so when you do discuss things with you OB you have a little information underneath you.
I didn't have a positive c/s experience because of my own situation but I will say that I have been told that a planned cesarean versus unplanned or emergency cesarean are night and day. Which makes sense considering your body wouldn't have gone through the process of labor/delivery already.