No you aren't unreasonable, but I'd also question whether it was the best thing for you too.
The issue is that its youd third baby and part of your reasoning is that you didn't make it to the hospital on time and your labour was so fast.
The problem is that this doesn't eliminate the same possibility. Hospitals won't do an elective cs before a certain gestation and even then they can't guarentee an elective even if you have solid reasoning if you go into labour before your planned date unless you have a physical medical emergency and its essentially a 'crash section'. Which might be a realistic possibility given your daughter's position.
I had a planned CS and the system is they couldn't guarentee what time you'd go in on the day you were scheduled. You'd be booked in, with an order slot, but you could be bumped if there was someone who was a medical emergency ahead of you. So you had to turn up and wait until they were ready and had a free theatre place.
The information I found when I was researching my options was that there were two fairly different cohorts for planned CS. The first were mothers who hadn't previously had a baby and the second who were mothers who had suffered from birth trauma from a previous experience. And generally speaking there was a difference in how they should be treated.
In mothers who were suffering from birth trauma it seemed to be the case, that they responded well to greater psychological intervention. What they needed was their fears being listened to and a more detailed birth plan needed which was better tailored to their individual fears and needs.
In your case, you need to talk to your midwife and push for this - you need your trauma to be taken seriously and ANY birth plan you have (be it a VB or a CS) needs to take into account your fast labour. You need to be reassured you will be admitted immediately if you do go into labour with your previous history - simply because if you do, your chances of getting to theatre quickly enough are probably limited. At that point, given the other risk factors, you may be better looking more generally at managing your fears because physically a VB will still remain less risky for you. Again this needs you to be talking this through with your midwife and getting them to acknowledge there is a mental health as well as physical issue with regards to your birth plan.
Above all else, you NEED to be discussing what would happen if you went into labour with a footling breech given your fast labours and how this would be managed.