Good Morning A.!
I have to tell you upfront that I am very biased when it comes to this discussion (so just know that as you read my answer!!)
I have had 2 C-sections and 2-VBAC's. My first child was a C-section as a result from a failed induction. (I was over my due date and the baby was large, so they decided to induce. They could never chemically/artificially get me into active labor. So after 24 hours of trying, the baby started showing signs of distress and the decision was made to do a C-section.)
For my 2nd child I found an OB/Gyn who was very supportive of VBAC's. (After having a C-section most doctor's wouldn't say it out loud, but there was A LOT of "encouragement" for me to just schedule a C-section and not even concider a VBAC. I even had one doctor tell me that I was being selfish for not doing a C-section.) Dr. Paul Corsi was outstanding! He looked at all my post-op notes and said that the OB who performed the C-section made a low transverse incision and stitched me up in such a way that the uterus would be a good candidate for a VBAC. He monitored me closely when I was in labor.. and we delivered a beautiful 8lb 12oz baby girl vaginally!!
Then my 3rd child while we were in labor (again planning on a vaginal birth) started showing signs of distress (heart rate plunging and not returning to normal after a contraction)Dr. Corsi tried every non-invasive way to relieve the baby's distress, but baby was getting worse.. so we went for an emergency C-section.
Baby 4.. back to Dr. Corsi and another VBAC. All went well, and little Nathan came into the world the "natural" way!!.
The first step (I believe!) to having a successful VBAC is to find a doctor who is committed to doing them. Due to the liability, I think that OB/GYN's would rather not even try. If you have a doctor who is just giving you the reasons not to have a VBAC, then if one thing is not perfect... they will be ready to cut.
Second, you need to be a good candidate. You sound like you are, because you had a successful vaginal birth before. The previous C-section needs to have been done with in the "safe" guidlines (the low transverse incision and no complications in the sowing back together) and the reason for the C-section was not due to your physiology.. but because of the position of the baby.
Third, I would make sure that I was delivering in a hospital that is equipped to do emergancy C-sections/Surgery. If by some fluke you do fall into the 2-3% that have a uterus that ruptures, you want to know that you are in a facility that can respond quickly. (When you have a second VBAC like I did your risk of rupture increases to 6 - 7%. On my second VBAC there was an instance where the baby's heart rate dipped one time and was slow to come back up... which can be a sign of uterine rupture.... with-in seconds I had 10 nurses,interns and Dr. Corsi in my room. They stayed until they could determine if it was just a cord/position issue or a true uterine rupture. 5 hours later Nate was born "naturally".)
For me the risk was 97-98% that I would deliver without any complications the first VBAC (which is the risk for a woman who has never delivered before) and 93-94% that it would be successful the second time was worth it. A vaginal deliver is so much easier to recover from and that is really important especially when you have children at home already!! I am thankful that all my deliveries have blessed us with healthy children and I am thankful for our medical professionals who assist us in this process.
I hope you find this helpful. Sorry that it is so long, but I have thought a lot about this topic!
I'll be praying for you!
Peace,
B.
P.S. If there is anything more specific you think I can help you with or you have questions about, I would be more than happy to help!