Girl,
Stop worrying about being perfect there is no such thing. Nobody is perfect and especially not at 17. You have a lot of growing to do and with time, you will find your place. You are not 18 yet, you are 17. You are still in high school and you have no idea what you want to be. With time, experiences and lessons learned, you will figure it all out. Stop stressing about silly things, everything will work out. Doesn't it always?
Let me tell you about love. You will find it and you will lose it. Love comes and goes. Love is not like in a fairytale where you only find it once. There are over 300 million people in the United States and if you really believe you will only love one person out of 300 million, you are wrong. You will probably fall in love with some hot older guy... let me tell you.. don't. Focus on you. Focus on all the things that make you happy. Guys will come and go. You are 17... 17! You have plenty of time to find true love. Use your time wisely by doing things that are going to define you as a person. Find out about yourself. Try new things, make new friends, don't be afraid.
Friends. They will also come and go. Make new friends. Find people who pull you out of your comfort zone. As you make new friends, still keep up with your old friends. Don't limit yourself to one person, be friends with everyone. One day you may lose every friend you have. Don't worry. Once again, you are only 17. Oh, and remember how I told you there are 300 million people in the United States... yeah that's 300 million people you are capable of meeting. Find a friend who actually cares about. Don't be friends with people who bring you down. Find friends who will hold you hair if you slip up and get too drunk one night. Find friends who you can do nothing but sit at home and have a good time with. Find friends who are worth your time.
So here it is. One thing to tell my 17-year-old self. Life will go on.
You don't need anyone but your family. Worry about you and you alone. You will find love and you will meet new people. Everything will crash and burn and you will rebuild. Don't stress.. even though I know you will. Life Will Go On.