AITBA for not offering my mom food?

For context this is the first time I’ve really had money to myself in my life and I got the check 2 days ago for my 18th birthday. I don’t have an issue with sharing my money at all, it’s just that i’m not used to sharing things or having money that I have to spend on myself or anyone else. I was hungry and so I spent my money to DoorDash myself food and my mom got upset that I didn’t offer her anything. Saying that my sister would’ve done it. I feel like it’s unfair to say that because my sister who is 31 has been getting money for years and is used to not only spending her money on herself. But I digress, I said “Oh if you want something I can get you something” but she refused it. It’s not that I didn’t want to spend the money or that I had a problem with it, I have enough to share but I didn’t think to ask because I’ve never had money to myself that I had to think about others with. She knows that I wouldn’t have a problem with spending money. I always share what I have with people if they ask. It’s just that I rarely ever have anything. I’ve always depended on other people so I didn’t think to ask someone else if they wanted something. So AITBA for not offering her anything?

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u/Whole-Powerful — 5 days ago