Don't freak out. It's going to be okay. One of the things you'll realize is that during your core rotations you will get exposed to a lot of the specialties you're mentioning (rads, neuro, anesthesia, derm). You will decide if you like to hang out in the OR (if not prob don't want gas). You will decide if you want to see patients (if so, prob no rads/path). You will also be exposed to things during your first two years. Definitely path. If you're still worried, spend some time during those two years shadowing docs in fields that you might be interested in but have no idea what exactly they do day to day. That also might narrow things down for you.
At my school we have six-week rotations in the third year and four-week rotations in the fourth year. We have a "surgical subspecialty" block where we have to take two different subspecialties and can choose from gas, urology, optho, neurosurg, ENT. Then we have four four-week electives. ER is required (it often is, check the curriculium at your school), as is neuro. A "basic science" is required which path fulfills. And we have two months of vacation, but if you want you can take extra rotations during that time. I felt that I was able to try everything I was still interested in trying by the time I got to fourth year and take electives in my residency field (and I've been done with school since late March).
I know that some schools really pound the family practice (sounds like yours might be one of them). Just use that time to 1. see if you like primary care and 2. learn about the other fields you will be exposed to during that time. That should also help you narrow things down. In general medical students aren't given much time to pick a field. But you gotta make the best of it and since you are thinking so far in advance you have a chance to spend some time really researching the different fields before you even get to clinicals. Congrats on starting this process!