People will tell you, "you're still young!" Others will tell you that "you have so much more life ahead of you." The one thing no one tells you is, "Look how far you've already come." You've already lived so much up until this point. You've grown, you've learned, and you've loved. You're the same person as you always have been, and at the same time you are remarkably different.
Chances are you've experienced your first love, your first heart break. I'm sure it hurt like hell. I also imagine that you learned a lot about yourself from it. You learned what you look for in a relationship. You figured out how to love someone else while still respecting yourself. In the end, you learned to cope with heart break and disappointment. You've also felt this in friendships. You have watched friends come and go. Some had your back, others turned theirs to you. You experienced feelings you will feel again at some point in your life, although it always feels worse the first time.
The further you get in your college career, the harder and more impossible it feels. When you stop and think about the things your younger peers are learning and reminisce on the times you thought that was impossible, you feel pretty smart. Even though it feels like it, this isn't beyond your capabilities. You will get through it, and you will graduate.
You've come pretty far, from learning to read, to first dance recitals, to first cars, to first legal drinks. Your firsts aren't over, and neither are your learning experiences. You change as your life changes, and that's more to look forward to.