Sister doesn't want to be involved

I am just venting right now. Me and my sister grew up as stepsisters where I was considered a scapegoat child and she was a golden child. Basically, I was raisee in a narcissistic household. But we were always still kind of close she is more level-headed and I'm more free spirit. SHe's always had things together and I've always been kind of go with the flow. Although in the past we've been semi-close we've gone through times where she will completely cut me out of her life such as not even telling me when her baby is born and I had to find out from a secondary source. She was there for me with my first child but ever since she had her second child she's been really distant and I've reached out multiple times in the past half year to hang out to spend time together that I want to see her kids and her excuses always that she is so busy. I finally told her that I'm pregnant again and she wasn't that excited for me and still made an excuse not to hang out with me this weekend. I think I have to come to the terms and realize that I'm not a priority in her life and I'm not really sure what the issue is. I did bring up to her that I'd like to see her more often and she kind of blew me off. She is older than me and we literally live 10 minutes away from each other. It's just kind of disappointing to be honest. I think it could be a product of how our childhoods were, I don't really know. She doesn't make an effort to be around my child either. In public she acts like she's so happy to see me and like nothing is wrong.