Do I have a right to be upset with my sister?

I live across the country from my younger sister and mom, haven’t seen my sister for about 8 years (since I moved away to my dad’s when I was a teen) and I’ve seen my mom once since then (about a year ago). Mom called me about two weeks ago, said her and my sister were thinking of doing a road trip to see our uncle and some of the family (who I haven’t seen since I was about 7 years old, my sister sees them about once every 1-2 years, I lived with my dad when I was young so they don’t know me too well and haven’t met me or my daughter or fiancé). I told mom that fiancé and I would have to take a trip to see everybody and we’d start saving up. She then shoots me the idea of if she helped pay for us to come too, so I could see everybody and see my sister for the first time in awhile. I get excited, plan on things we can possibly do with my sister since I haven’t seen her in forever. I tell her though to see what my sisters opinion is though, and mom calls me a couple days later and vaguely says that my sister was definitely not interested in me coming and I guess she wants alone time with “her uncle” (he’s mine too lol). I was honestly stunned. We aren’t close like we were when we were little but we certainly aren’t on bad terms, we’re both over 18, we’re adults and I figured she’d be happy to see me. When I lived there she was jealous of me and accused me of being the “favorite” (which I don’t understand as I only lived with my mom for a handful of years and she has grown up with her and all of that side of the family), but that was when we were kids and doubt it’d be relevant now. I don’t know if I should message her or what, I’m just confused? We can plan our own trip to see my uncle and all of them, I just dont get why she’s so offended at the idea of me coming and being there with her. Advice?