How to counter “autism isn’t an excuse”?

I (18) recently snapped at my younger sister (13), telling her to shut up. She tried to get involved with my car insurance when I was already hungry and stressed. She retorted with “Autism isn’t an excuse for being rude. You need to control your emotions.” She frequently tries to involve herself in my business, I understand she is trying to be supportive but I am quite literally an adult and it comes off as infantilising. Due to the frequency of this, despite already speaking to her about it, I have lost my tolerance and so snapped back immediately. I somehow managed to not blow up at her but I was completely lost for words. I’m trying to figure out how to explain to her how I feel (with an apology) and am also wondering how I should counter that sort of language in the future.