Are you nervous about entering college or feeling you won't fit in? That's perfectly normal since college is such a new experience. While everyone is going to be nervous when entering college, hopefully, having a perspective from someone who's already gone through it all can help calm your nerves a little bit.
Everyone else is as nervous as you are. I know it's something your parents have said, but they're right. No one knows what they're doing with their life at 18, so you don't have to either. But seriously, everyone is going to be nervous and they won't be watching you. They'll all be focusing on if someone is judging them, too. You might have heard that upperclassmen are judging you, but that's wrong too. Upperclassmen don't care either. They know what it's like, and they want to be out of college. And if you get lost or confused, you can ask them where things are.
Not only is no one going to judge you about your first-year status, no one cares about your high school days. You have a fresh start. High school you is basically preschool you for all that it matters. You have so much room to grow in college that you won't be the same person at the end of even your first semester as when you started. And those kids who went to your high school? Unless you have the same major or dorm, you won't see them that often. I watched out for my old classmates and coworkers, and I saw them all about 20 times over a year combined.
Once you get to college, you are going to have so much more free time than you did in high school, especially if you live nearby or on campus. What's great for that is that there are SO MANY CLUBS. There is probably a club for whatever you like to do, and if there isn't, you can create one. Word of advice: don't sign up for every club. Limit yourself to a few at first or you will get overwhelmed.
But the best thing about college is the scheduling. Your class schedule is your choice (mostly) and you can usually make it how you want it. You don't have anyone forcing you to get up for classes at 7 in the morning (unless you're into that), and you get to choose your lunch time. As someone who always had the latest lunch at my school, I loved being able to eat whenever. (If you care about weight, you might want to workout to avoid the Freshman 15.)
Classes are also so different from in high school. Everything your teachers have said about college is probably false. Professors generally don't care if you're on your computer (especially if you're in a gen ed class with hundreds of other students). I've spent entire classes on Pinterest while eating Poptarts (although I don't recommend you do either of those things). For smaller classes, you might want to pay attention, but it's up to you. If you're late, your professors won't stop you, even though you might annoy your classmates. I will say you should take notes.
So while you're getting ready to leave your parents and go to college, just know that it is not as scary as you think. Get ready for 4-ish great years and the growth of who you are.