To my 18 year old self

A while ago I did a "letter" to my 16 year old self.  After some recent events, I decided that I needed to a letter to my 18/19 year old self, mainly because one of my best friends has needed some "inspiration" lately.  So here it goes:
Dear 18/19 year old me,
Congratulations, you have graduated high school.  A place you loathed for many years due to its cliques, fat jokes, and all around anger.  While I choose not to dwell on that place for too long, I want you to know this: don't judge others based on what your friends say.  If you made friendships based solely on what your friends think, you would end up a very lonely person.  Lindsey ends up becoming a dear friend who helps you tremendously  in 4 years and Rebecca becomes someone who can share everything with.  Trust your gut, not what others tell you.
Secondly, don't become so over involved with boys.  The one you love isn't going anywhere.  It's fun, shiny and new, but don't leave your friends just because of him.  Car ends up becoming one of your best friends whom you have some incredibly good times with, even though you pour yourself in to a relationship.
You do have to go to class in order to be successful.  It isn't like high school where you could skate by and still get good grades.  And while we're at it, those poor grades haunt you throughout your entire academic career.  Stop drinking and start studying.
Quit being the obnoxious girl at hockey games.  No one likes her, I promise.  You just look like an idiot.
Clothes and brand names do not prove you are a better person.  Good people like others based on personality, not by the materialistic goods you seem to spend money on.
Go to the gym, everyday.  It makes your life so much easier when you're older. 
Be nice to your sister.  She really does become your best friend.  Help her enjoy her last years of high school, and remember to let her live in her own mistakes.  Be there to support her when things go badly.
Don't make someone a priority when they make you a convenience.  This includes friends.  If you're the one constantly making plans here's a newsflash: they don't care about you.  This applies to friends you've had for a long time.  It isn't worth the anger to be friends.  Even if they ignore you when they see you.  That's not the definition of true friendship.
The next few years will be fun for you, enjoy them, but not too much!