@TomorrowToday
In the past 18 months , how many of your family members have you visited? Why were you making inquiries about your sister's wedding, thus putting other family members in an awkward position!?
You are NC with your sister, it is tube of you to make inquiries and try to get them to tell you information that she herself would not share with you.
In this case the consequences for being NC was the lost opportunity to be present at an event with other family members, and the lack of awareness that the event took place.
Your parents and other siblings probably do not like the awkwardness caused by the NC relationship between the 2 of you. Seemingly, they have all made the wise decision to have no part in it.
The decision to go NC comes with an opportunity cost, and it seems as though you are experiencing that cost at this moment. It was and should not have been their concern as to how or when you learned of your sister's wedding. You and your sister have the relationship that you have, and even if your family thinks it to be immature and unnecessary, they are respecting the decision that the 2 of you have made.
You seem to think of yourself as a victim in this situation, but what has stopped you from visiting your family in the 18 months post Covid? What had stopped you from calling or sending a note to your sister wishing her well on this new chapter in her life?
Unfortunately, you are reaping one of the inevitable consequences of going NC. You and your sister chose this path, but it is not a journey that other family members will choose to take with you.