You're only in your first year of undergrad. Lots of people resit modules once, sometimes even twice (there was one girl at my uni who resat second year twice and first year once...I mean, at that point it might have been better financially to give up, but she certainly had a solid grasp of the first and second year subjects after that). Even if you get a good grade and pass a module, you may then come back to that a couple of years later and realise you didn't actually understand it that well, but have since improved.

No one is amazing to begin with. It takes time, practice, doing other modules and learning other stuff to fully appreciate things sometimes. The best thing to do is to not get defeatist about something you've only just started.