So you have literally said you aren't close but love her, I think she probably feels the same way? Unsure why you would think you'd get a heartfelt shout out when you aren't that close? She wants you involved because you are family and she likes you….maybe you should just be happy? She's your husband sister and she still wants you there, family is important to her, she considers you family….it's actually nice? I think your expectations are making you sad about this when really you should take it face value.
This sounds like exactly why age gap relationships can be problems. You are at different places in your life, I think best to let it go.
So you have literally said you aren't close but love her, I think she probably feels the same way? Unsure why you would think you'd get a heartfelt shout out when you aren't that close? She wants you involved because you are family and she likes you….maybe you should just be happy? She's your husband sister and she still wants you there, family is important to her, she considers you family….it's actually nice? I think your expectations are making you sad about this when really you should take it face value.