I work with college students and, more often than not, the things they struggle with have nothing to do with their intelligence or academic requirements! They struggle more with the best ways to manage their time and expectations. And, they are reluctant to ask for help until they have already started drowning.
Becoming a college student and starting a career does NOT mean that you have everything figured out! It means that you are choosing new experiences and environments to help you become more independent. The best thing you can do is find out what help is available BEFORE you need it. Then, build a support system (parents, teachers, academic resources, mentors, friends, etc.) that you can rely on when the time comes for you to get extra help.
Don't be afraid to try new things and understand that failure isn't fatal.