I would actually go farther than @CheddarcheeseMN: talk to your advisor when you get to college about research opportunities, aiming to have one in place by the summer. It will not be “your” research- you need to do supervised research, which initially may be less interesting to you. As you go on, get more experience, learn more about who is doing what research, learn more about the field you will be able to home in on ‘your’ area of interest.
Our current PhDkid spent every summer of college doing full-time research, as well as in-term research for 3 of the 4 years. The LoRs and some specific research expertise from that work were a big part of why she was successful in her PhD applications, and (just as importantly) they laid the base for a happy PhD experience.
bwahahahaahaa…you not only ‘can’ but you have to! But waaaaaayyyyyy more than I think you are thinking- more like a sub-sub-Subtopic. That’s why you have to be sure that you are really, truly interested in your Subtopic- you will spend years (sometimes an entire career) marinating in it. Happily, you have some ideas as to what you think you are interested in, so start there & be prepared to have your interests morph- sometimes in increments, sometimes in big turns.