WIBTA if I stopped being available to help my younger sister with her university applications after she told my parents I was "too harsh" when she asked for my feedback?

So a bit of background. I (26F) went through a pretty competitive application process for my graduate program two years ago and came out of it with a solid understanding of what works and what doesn't in personal statements and motivation letters. My sister Lena (18F) is applying to universities this year and about two months ago she asked if i would help her with her personal statement. I said yes and was genuinely happy to, I put in probably four or five hours across two sessions reading drafts, leaving detailed written notes and doing a full rewrite of her opening paragraph as an example of what i meant. My feedback was direct. I told her the first draft read as generic, that two of her examples didn't actually support the point she was making, and that her conclusion repeated the introduction almost word for word. I also told her what was working, which was quite a bit actually. I thought I was being the kind of helpful that actually helps, not the kind that just says "this is great" and sends you in underprepared. She said thanks, seemed fine, and I didn't hear anything more about it for about three weeks. Then last Sunday my mom mentioned casually over dinner that Lena had said i made her feel bad about her writing and that my notes were "demoralizing." I had no idea she felt that way because she never said anything to me directly. My mom wasn't accusatory about it, she was just passing it along, but it stung a bit. I spent real time on that feedback. Now i'm wondering whether to keep offering help or just step back and let her figure it out with someone else. I wouldn't say anything to Lena about it, i'd just quietly not offer anymore. WIBTA?