I’m eloping - mom knows, please help me with what to say

I’ve lived in a different country for a year now with the love of my life. We’ve decided to elope before I take a trip back to my home country (US). I planned on telling my family the exciting news face-to-face as soon as I return in two weeks. That did not go as planned, there is a document that I needed from the US so I called my mom and told her everything and asked for her help with the document. Now she is upset that I haven’t told other family members, and she is telling me that I need to tell them. Her exact message was:

“It's important to me that you reach out to [NAME] about your exciting news. He is happy for you but bummed that you don't include him. He may only be your step dad but he's always been there for you and would like to be included in your life decisions. Does that make sense?”

I don’t feel like anybody is entitled to my personal decisions, even close family. I think I can share as little or as much as I want to. I don’t know how to explain that to her in a way that she can understand and that is still respectful and doesn’t come off as rude. I’m asking for advice as to how to explain this, because I’ve read some of you on here put it so eloquently before and I don’t have the words in my brain right now 😂