I feel so gullible

I was dating this girl (for context we are both in our mid 20’s) who invited me over to her place on the second or third date. I brought over flowers because I thought that would be nice. Fast forward a week later she mentions that it was rude of me to not cut/shorten the stems of the flower. She said it was like giving her a chore to do it her self and that it was inconsiderate of me. At that time I apologized and thought it was my fault… I know now that no way me bringing flowers was inconsiderate, but for a bit I really believed her that I was in the wrong. I know that there have been other people I’ve felt with where I’ve believed I was in the wrong for something and quick to apologize only to realize later that I had done nothing. I guessing I keep falling for this because I like to think the person I’m talking to has the best intentions or knows something that I don’t, but this instance really stuck with me because it seemed so ridiculous. Can anyone else relate to this or have advice for how I can avoid falling for something this dumb next time without also having to feel guarded from others and what they say?