Holding a 90%+ loser for 6 years: when do you finally move on?

Back in 2020, I bought into NIO during the EV hype. I was 18, had very little investing experience, and got caught up in the excitement. Today my position looks like this: 141 shares Average cost: $47.79/share Unrealized loss: about $6,000 (roughly -90%) At this point, the position is worth only around $700. I’m not asking whether NIO specifically is a good company or for personalized financial advice. I’m more interested in how experienced investors think about situations like this. I’m starting dental school soon and moving into a new place, so selling the position would give me a little extra cash and, more importantly, let me mentally move on from a mistake I made when I was younger. I’d appreciate to hear how others think through these situations and what investing principles they use, regardless of whether the stock is NIO or something else.