I Have a Half-sibling I've Never Met

20 years before I was born my mom gave a baby up for adoption. She had 2 more babies in 5 years that she kept then me years later. My adopted sister found us and is coming to meet us soon. My 2 older siblings are freaking out and can't wait and took a week off work to be with her. And I'm just meh. She's old enough to be my mom and has kids my age. I live alone with nobody to help pay my bills. My siblings are giving me the 3rd degree for not taking off work. I didn't invite her here. I'm willing to meet her but on my schedule. Am I wrong?