Wedding invitation brings up some memories

Hey everyone,

I got a wedding invitation from an old friend recently. The last time I tried to contact her, which was years ago, I sent her a friend request on Facebook but she rejected it. We used to hang out sometimes as children, but we were never really close. I'm not a spiteful person but I can't let go of that I felt rejected when she denied my friend request. Yet her mom says that her daughter considers me to be her sister. The difficult thing here is that our families have been knowing each other for years, particularly my mother and hers who are kinda close so I felt pressured to attend the wedding.

I grew up in a modest family and we've had some financial hardship and sometimes things were serious. My mother's friend is aware of this situation and is generally understanding. However, there were some episodes that my mother recounted in which she had noticed her friend would never ask her to join her group of friends for lunch or dinner because they went to mildly expensive places.

I told my mother that if this person was a true friend, she would ask her to meet in a cheaper place just for the sake of sharing a moment between friends. I feel that Bride's mother friend has some hidden sort of prejudice about our situation and that makes me feel like she looks down on us in some way. Their family have a comfortable financial situation and they own their house. Personally I don't like the my mother is treated by her friend.

To add to the wedding, I felt the bride (the old friend) wasn't truly happy to see me there. I'd be curious to know why would she invite me when we haven't seen nor spoken with each other for 10 years.