I Did My Sis's Homework For Her And Now She Thinks I'm A Genius

So my sister, Lily, she’s in her first year of college and started this big physics class. You know how it is, college courses are like a whole other planet compared to high school, and she had no clue where to start with all these equations and theories. Well, I’m the oldest sibling, so naturally, she came to me for help. Problem was, I have zero interest in physics; it’s just not my thing. But I didn’t want her to fail or be stressed out, so I offered to do her homework for her. It seemed like a quick fix, just type up some stuff from my own college days and send them over. Lily was super grateful at first, even sent me one of those cheesy thank-you texts with all the emojis. But now she’s coming around asking more questions, wanting to know how I got such high marks in that class way back when. And guess what? She's planning on doing another physics course next semester. I feel pretty good about helping her out at first, but now it feels like a bit of a scam. Am I the asshole for not telling her straight away and maybe pushing her into something she might hate just as much as I did? So yeah, here’s my question: Did I make a mistake by doing all this for her? Is there anything wrong with me being proud that she thinks so highly of me even though it's kind of fake?