Most Helpful Girl
I was taught by my parents to make this sort of decision for myself, based on my own beliefs and needs. My brother was taught the same. We were taught that as things change, so we were entitled to change our minds, if our experiences told us we were on the wrong track.
Your daughter is now well into her formative years, and has come to the conclusion that eating pork is wrong. You and your husband must honour her decision, and do everything you can to facilitate this. If it means cooking something else for her, it is not a big issue, is it?
In fact, get her to do a lot more cooking. Not just for herself, but for all of you. Why? When I left home to go to uni, I was a very capable cook, and was well able to fend for myself. Your daughter, and any other children, need to be the same.