Although religion wasn't an issue, I was the 'first in' to an old-fashioned, set-in-their-ways, rather snobbish family who found me 'common' (not actually said until years later, as an example of how far they had come, but believe me, I knew!)
I felt some resentment as subsequent partners joined so much more easily, but decided, as others have advised to 'park' my annoyance. It was helped by the advice often given here, that they have raised this wonderful man I love, so they can do something right!
The family changed for the better as they learned to do things differently, and I learned how tolerance and understanding can grow. I had come from an open and welcoming family, and hadn't realised the barriers some people have to climb to accept those who are slightly different.
So, I agree, you have a right to your feelings, but no need to parade them. Quietly congratulate yourself!