You will be fine. On the day, once you're holding your baby and it's over, you'll be so relieved and amazed that everything is okay that you won't be able to stop grinning.
I had an emcs after v traumatic time with dc1 and then dc2 was another emcs but without the trauma. I was terrified throughout the second pregnancy. Not because anything went wrong, not even scared of the cs tbh, just a nameless, faceless, all-pervading anxiety. Some days, I couldn't look at dc1 without sobbing. I thought I might die suddenly from preeclampsia or a haemorrhage or a complication with the anaesthetic. I knew, logically, all of that stuff was extremely unlikely, but I had these strange, unfounded fears.
I think in retrospect it was because I associated labour with being out of control, with fear and with things going wrong. Well, if you're having an elcs and there won't be any of the unknowns from labour and natural delivery, I think you possibly just escalate the fear to a belief that the cs itself will surely go badly wrong.
The one thing that helped the most was telling the team on the day. They were so gentle with me. They wrote all over my notes that I had a previous traumatic delivery and emcs and was suffering with anxiety. Every member of staff from the people doing my pre-op stockings and bloods, to the surgeon and the anaesthetist were made aware of how worried I was. They are always kind and lovely but they were just perfect. They asked me what I wanted and they made me think about what would not happen, not the threat of something that almost certainly wouldn't. So they made me consider real options like lowered screens and DH watching and skin to skin. Then I was focusing on what was real and not the fear. They were bloody brilliant and they made my second cs such a healing process. I loved it!