Is it okay if I haven't figured that out which course to take in college?

Hi Ciara, 
When I was in college, I actually didn't decide on an engineering field until mid way through my freshman year! It's great that you already have the field picked out! My advice would be to take a look at the different college you are interested and see when you need to declare the specific field. Many of them may not require you to pick a specialty until your sophomore year, which gives you time to explore them in more detail. 
My second piece of advice would be to think about future careers in each of the specialties and how that aligns with your personality. For instance, do you see yourself in a lab setting? working at a plant? 
The best part really is that there is no right or wrong answer. Even if you are mid0way through your college career and you decide that you want to switch, that is always a possibility, just know it'll add time until you graduate. 
Good luck in your decision! You will be great!
Kristin