But having an idea of what you might want to study/practice does have some awesome advantages.
Also, people notice when you're passionate about something. You'll stand-out among your peers.
What are you passionate about in general? What drives you? What gets you out of bed every day? What inspires you? What do you value?
I greatly value tech and speech.
There's likely a legal field, or area of study, that matches whatever it is you're generally interested in or passionate about. Figure out those interests first. Match them to a legal field last.
Then you might thrive with human rights law, immigration law, family law, criminal justice reform, etc.
You might find your niche with Internet law, telecom law, privacy law, AI law, etc.
There's something out there for everyone.
When you listen to the news, what topics fire you up the most? What are you an expert in? What is your "thing"?
If you're a 0L, consider using your summer to learn more about yourself. Indulge your intellectual curiosity. The legal field (and career) will soon follow.