I had the same worries when I fell pregnant with my second baby. I had to have an emergency c section with my first DD as after 31 hours of painful labour (due to epidurals not working). I eventually had to have a general anaesthetic as they started the section before my spinal block took effect!

Basically DD was back to back and would not come through the pelvis.
When i fell pregnant again I really wanted to have a natural delivery. I was told that it would be possible. Hospitals here are very reluctant to schedule C sections. You can't request a section. The NHS are trying to get their C sections rates down.
As time went on it became very obvious to me that baby was back to back again and I started to worry. By the time I got into the third trimester and baby was big it was very clear that baby was not in the right position and was in fact in the same position as DD1. I saw the doctor and shared my worries and was told that baby was not back to back. (She was - you could see her fett sticking under my skin). My worry was another emergency section due to the horror i experienced the first time. I was told that I WOULD be trying for a VBAC and they would not schedule a section under any circumstances.
So my labour starts and in contrast to the last time it went very quickly. Afetr 2 hours I was 10cm and just arrived at the hospital. So no pain relief was available. I pushed for 2 and a half hours and nothing happened. Surprise surprise they found she was back to back and totally not coming down. My pelvis seemed to be a problem again. So they decided on a section. I was scared but the anaethetist was a young girl and i told her about the last time and she was amazing. It went slowly so i was sure i was numb and it was a totally different experience.
I did feel annoyed that they had made me go ahead with natural labour knwing the chances of it being a success are slim.
I was also disappointed that I didn't get the chance to experience natural labour but I am grateful for a lovely delivery none the less.
So if there is a chance that you could get a VBAC then go for it and push your case. I would have loved to get one. But at the same time whatever happens try to make the best of it. The end result is the same hopefully and you don't get a medal for pushing a baby out the natural way!!!
As long as mum and baby are healthy then it really doesn't matter.
As for me I am not having any more so I will never have a natyral delivery but I di have 2 beautiful girls so can't complain too much!!! (except for the lovely scar line! My battle scar!)
Good luck and enjoy your pregnancy!