I am late thirties getting married this summer. My parents 'christened' me a name which I won't reveal as it is too identifying, but let's say Katherine. Since I was aged around 8 I have been known by friends as a common abbreviated version of the name, let's say Kate. Literally everyone except my parents call me Kate. Then when I started my professional life in my early 20's in my first job there was another Katherine in the office I worked in, and so to avoid confusion I started calling myself Kate on a professional basis as well, and signing myself Kate, business cards etc etc.
So for the last 20 years I have been Kate professionally and personally and only Katherine to the bank manager. Most people don't even realise my birth name is not Kate.
My parents have consistently refused to call me Kate throughout the last 30 years. I have a little nephew who calls me "Auntie Kate" and when my parents talk about me to him they use "Auntie Kate", but to my face or when talking about me to anyone else they always use Katherine. I have asked that they try to use Kate as I much prefer it but they refuse, saying that they christened me Katherine. I am also not religious and never have been, although they are both churchgoers.
I could put up with this as at the end of the day it doesn't really matter if they insist on calling me a name I don't like - it's their problem. However, as I am marrying this summer and have decided to change my surname and I would also like for formalise my first name as Kate and I want to do this before the wedding. The main reason is that I don't want to stand there and say "I Katherine, take you DH" etc - as it feels completely inauthentic. I want my wedding day to reflect the true me and in my heart I feel I am Kate. My DP knows me as Kate as do all my friends and the rest of my family (which only consists of a sister and nephew). Saying Katherine only brings up feelings of being controlled by my parents and upbringing and feels negative - not what I want on my wedding day.
My parents are elderly, not in great health and stuck in their ways. They are old fashioned and concerned about what people think. I don't want to upset my parents but should I just change my first name by deed poll before the wedding? But does this cause world war 3? What if they hear me say my vows as Kate and get upset on the day? I have asked them to change how they address me but they refuse and do seem very adamant / angry about the whole idea. It makes me feel like a child.
Btw my parents are paying for the wedding (!)