I had this exact scenario. Agree with lulumama that there are some good threads on here to have a look at.
Essentially, I was so distraught after first birth experience which ended in emergency C section I was convinced I wanted to have a C section straight away with my second birth to avoid any further birth trauma.
I had to go to see the Consultant Midwife and really fight my corner to have one. I eventually convinced her because she told me significant mistakes had been made first time round and that she could see I had been psychologically affected by the birth.
The NICE guidelines are worth a read and despite what people say, noone can make you have a natural birth if you do not think you are able to do it.
HOWEVER, having "won" my right to an elective c section, I started doing further research. I found that there was a team of midwives near where I lived who were exactly that .. a "team" of 7 midwives who would all see you at some stage during your pregnancy. I switched to this team and found that the care I received in their hands was marvellous. I came to really trust them and their views. They persuaded me to try for a VBAC and eventually I agreed. I went to relaxation classes, listened to relaxing music and had the most amazing birth. I bonded with my new daughter instantly (unlike with my first child). I knew the midwife who delivered me.
Anyway, all that to say, that it is totally up to you.. speak to people, read the threads on here and read the NICE guidelines. And whatever you decide to do after all that will be the right decision.