I grew up in an environment where faith was unquestionable. We didn't watch television unless it was the news, we didn't listen to the radio because songs were perverse (satan!), and we didn't have much alone time because that is when satan tempts you the most. There were too many of us in too small of a house. 5:00AM we'd wake up and read the scriptures as a family. I was raised in the church and knew the teachings at a young age.
When I was 6 my Great-Grandfather passed away so I went to Mexico for his funeral, there I was raped by an older cousin.
First of all, this skewed my perception of familial love. It has arguably fucked me emotionally over with men.
Second of all, (while it was happening) I remember thinking that it would be okay, I fought and "I'm not 8 yet, Satan can't touch me, God will come". I was expecting an angel to come and command him to leave or God to smite him, but nothing happened.
No one came. Well, he did, right? (see you need [black] humor if you are going to leave the church because I am telling you right now YOU WERE MIND FUCKED the entire time you were there and it is going to take you awhile to straighten it all out and find out what is REAL. You need to laugh, it really helps)
I remember crying, from physical pain but mostly from spiritual pain. I felt forsaken. I felt like my life was ruined forever. Never would a man want me, I wasn't a virgin. Never would I get into the celestial kingdom. Never would my family accept me, they would have told me that I should have had stronger faith (this is me going back to what I felt then, now that I am older I am sure they would have been more compassionate). I never told anyone in my family until this year, and I am now 19. I lived with that for a long time, and the only person who knew was my first boyfriend (age 14).

I saw from a young age how everyone around me was believing a lie and when you questioned it they questioned you and blamed it upon a metaphysical arguably non-existant being that had taken control of you.

El diablo!!!!!!!!!!!

What I can say is, watch out with the real world. You have lived under so many rules for so long you will not know how to function in society.
Your friends in the church will see it as Satan having got ahold of you. Some will try to get you to come back, and some will not even make contact.
Your family will probably be disappointed. Expect there to be high tension and for your relationship to dwindle. It is the equivalent of finding out your loved one has multiple personalities almost. YOU ARE TO BLAME FOR LETTING SATAN GET AHOLE OF YOU AS IT IS SATAN THAT IS DOING THIS TO YOU. You will be a sinner, an ash...essentially... of what was their child.
Your mind will unravel and you will truly begin to see and know things, instead of just get a fuzzy feeling after hearing the entire ward sing "God be with you till we meet again" (I fucking love that song).
Also, the impending doom of the apocalypse (end of times) will forever ring in the back of your mind. I recommend getting into Zombie movies, it dulls it out and gives that energy a sort of outlet.
Since you will be able to: have sex, drink coffee, drink alcohol, do drugs, watch porn etc.
I want you to know when I was faced with this I didn't know my limits. I had only known the limits of the church (and the limits of life extend way beyond that, I think there are none really only the ones you set for yourself). So be cautious. Don't become addicted. Realize that the substances cannot substitute for the "faith you once had". Replacing one type of denial for another is not really moving on, but staying stuck.
I recommend reading, honestly. It will help keep you sane and it will feel...serene. It'll wash away the old and show you new ways to see the world and life.

It is completely worth leaving and living a substantial life. If you want to be a good person, be a good person to others. I still help people out and I am very compassionate. I do it because I want to, not because I want a certain slot in heaven.
You will be tested (not by God directly, but your own limits and your will as a human being), you will walk through fire, and you will change and you will KNOW the difference of what it is to feel and what it is to know something. You will love many times, and your life will open up.
Mormonism is a type of childhood. It is ignorance, it is willful ignorance. It is a little bubble, it's a pretend land to keep the boredom from coming and the monsters away. It is thinking that there is a monster under the bed. Once you look and see nothing is there...it gets better.
You just have to have the balls to do so.