This might just be word choice, but “deciding” on your areas to be passionate about seems counter to following your passions. You discover your passions.
If you are passionate about something, by all means make it a priority. All the better if this is something that might translate into a college major. However, colleges like musicians and athletes who don’t major in music or play on a NCAA team. It is about the qualities it takes to become really good at anything, not necessarily what you are good at.
As a high school freshman, you can prepare for college by taking the level of coursework required by the type of college you want to attend. You can take electives and participate in activities that sound interesting. Then, make the time and take the effort to follow the passions you discover.