Loulou, you are not being silly. It is how you feel, and your feelings are important and should not be dismissed as "silly". I absolutely don't mean that you are right, but you need to deal with, and clear, that feeling. Everyone on here is giving you love, so take strength from that.
I did not have a cs, but a pretty horrible first birth (vaginal delivery with all sorts of 'fun' interventions.) When I was pregnant with no.2, I went to see someone for hypno-birthing. She was a qualified counsellor too and during one of the hypno-birthing sessions, I realised I was still really upset about what happened and terrified of it all going that way again. I ended up having counselling at that session for my birth trauma and it really, really helped me see things differently.
I think it is because if you plan for your birth to go a certain way, (all that making a birth plan, let everyone know your wishes, etc) and it doesn't go the way you expected, then that's when you feel a failure, or feel traumatised or distressed about it. Of course, not everyone does - just some people do! A friend who had planned a nice, calm elective cs ended up having a sudden emergency one under GA and was understandably just as traumatised by that!
Lots of love to you, see a qualified counsellor, phone her and get a feel for her manner on the phone - or better yet, a recommendation from someone who's used her. Good luck. Enjoy your lovely babies. They don't care how they were born! (think maybe your mum was just being a complete thoughtless twit like mine often is!)