Zebra
A couple of things that might be of interest to you.
Studies have shown that as many as 1 in 10 to 1 in 6 women may suffer from fear of childbirth which is problematic. The subject is simply a taboo one.
In 2011 the NICE guidelines on CS were updated to include references about requests made for an CS on the grounds of extreme fear and anxiety. This reflects the fact that tokophobia (an extreme fear of childbirth) is now an officially recognised medical condition.
These guidelines actually say that they do not know how to deal with women who have this problem. Counselling and extra support during labour for a VB have been suggested as ways to deal with it, in addition to allowing CS in these cases. There is no definitive treatment as no one really fully understands the problem. I suggest that there actually never will be as I think fear of birth probably covers a range of different reasons and triggers which people cope with in different ways. For some a vb homebirth seems to be the way to go. For others getting a doula. For others a CS. And others still to reach the decision not to have children at all. You just need to find what fits you.
The research in this country on tokophobia is limited but some research has been done Scandinavia which is slightly better. It seems to suggest that women who have primary tokophobia (fear of childbirth when a woman has had no children), have similar characteristics. A history of anxiety problem is one.
Another is that it can often start when you are a child and can be related to an experience or very negative association to do with childbirth from an early age. So having a mother who had a bad experience that she recounted to you, could have an influence and does fit with this suggested pattern as you suspect.
Having said that, and I do think this is pretty important to you, given what you've said - there have been studies into whether the experience of your mother is likely to repeat itself when you have a child. To date NO study has found a clear or significant link between birth experience between mother and daughter; it seems to be more down to the position of the baby and other more complex factors rather than purely what happened to your mother.
I also know there has been argument about diagnosis of pelvic disproportion in our parent's generation as being over diagnosed and was often in fact down to other factors (such as I mentioned before, position of the baby or birthing position of the mother) rather than truly about the baby's head being too big.
This doesn't necessarily help as if you have such a deeply ingrained belief it is hard to separate your feelings from what seems to be the scientific evidence as we tend to give much heavier weight to our personal experiences and those close to us than a bunch of figures we are unconnected with. And yeah its possible that this could mean you are more stressed about birth in general and this might affect your experience anyway.
In your favour, is you know this is an issue, so you have the opportunity to find a suitable way for you to deal with it. And you are talking about it here, rather than suffering in silence about it. Thats a big positive.
I think the best approach to start to get an idea of which way to go and what your biggest hang ups are is to write down what each little thing that bothers you, and try and address them one by one. Understand your fear and it puts you in a position to know how to cope with it better.
You are not unusual and you are not being in any way pathetic. Like I say this is a taboo subject, which is really not being helped by a number of very inaccurate and damaging myths out there, precisely because people don't talk about this. Childbirth IS one of the most dangerous and difficult events in a woman's life; it is perfectly understandable and natural to have fear of that. Its not weak. Its not always simply a case of just being able to 'get on' with it either - in the same way a depressed person, can't just 'pull themselves' together - some people need help and extra reassurance compared to 'a normal person' to deal with it.
P.S. Do this at YOUR OWN pace. Do not be pressured by family or friends around you, as you already have enough from your own anxieties to deal with.