VBACs are 80-85% successful, especially when ZERO interventions are engaged (no induction, epidural, laying in bed on your back, etc).
I had a failed induction turned cesarean with #1... did my research (I recommend you check out www.ican-online.org!) and tried a home birth with #2 this last August. Was doing well until about hours 12-14, when I was stalled at 7cm and 100% effaced. The Midwife and I decided I'd go to the hospital around the 14 hour mark due to failure for baby to descend. Another 10 hours of augmented labor and an epidural... baby still wasn't descending, tho I was 9cm... had another cesarean.
Reasons for this was baby was 10.8lbs at birth and his head and chest circumference were very large. They think it was due to gestational diabetes, but I had passed that test. Next baby, I will try for another home VBAC and will follow a diabetic diet to ensure baby isn't as big. The very VBAC supportive OB who did my surgery said that if the baby was even 1;b less, I would have had a successful vaginal birth.
If your OB isn't enthusiastic... your chances are low you will be allowed to have a trial of labor and they will endorse and force another surgery on you. If you had opted for a Certified Nurse Midwife at an autonomous Birthing Center... your success rate would increase. The ICAN website will let you know if your OB practice follows VBAC friendly guidelines or if they are just giving you lip service.