It can be difficult managing time appropriately your first year of college because you have a lot of new found freetime in between classes compared to high school, but on the flip side also have a lot more work/effort intensive projects spread out over time so you have to learn how to manage the studying and the play.
Adding a part time job or extracurriculars to the mix can give you less free time, but can also introduce a nice element of structure to your day, much like high school sports or other extracurriculars did. I often found that the more structure I introduced into my schedule, the more I tended to get done, because i didn't leave a lot of times for lounging around or distractions, as can happen with free time in college!
You can always drop a class in the first few weeks without penalty if your courseload seems like too much, or on the contrary pick up a part time job if you find yourself having extra freetime. It might take some trial and error at first but you'll get into a routine in no time at all!