Does anyone else have this problem?

I feel like I'm too much of a pushover. I was at an event earlier today and my cousin (30) asked me to go to her car and grab her slippers. I didn't think much of it and go them since I assumed her feet were hurting. Her shoes were pretty high and I know she has a handicap sticker. Not sure what her handicap is though as I've seen her walking. Afterwards, my mom mentioned I should've said something instead of just going. How did anyone overcome being too passive? I feel like I'm too old to be like this
Does anyone else have this problem?
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