Will God still have mercy on me for the almost eighteen very sinful years I've lived?

[Never thirsty!]

The most recent sin that tops the severity list: I've been kinda drawing power from demonic forces but I didn't actually know I was till about three days ago and haven't done it since next on the list: I tried but failed to take my own life
next I've been getting into fights almost every day since I was twelve breaking their bones and choking them out(the Jiu-Jutsu training comes back to bite me) the least horrible sin I've committed is probably the many lies I've told to make myself feel better because I'm so deeply broken and almost everything in between... Almost

[drill]

"Truly I tell you, people can be forgiven all their sins and every slander they utter, but whoever blasphemes against the Holy Spirit will never be forgiven; they are guilty of an eternal sin.” Mark 3:28-29

[AndrewinIce]

God can forgive anything in any amount. Being saved, being owned by God, isn't about sin. Its About the Blood of Jesus.His blood covers all sin, and washes it away. As Christians commit new sins, they are forgiven if they ask, just like that. Nothing else required.

God loves you, and wants nothing more than to be close to you. He will forgive you if you ask. He died for you. If no one else in the entire history of the world would have gotten saved, if only you in all the billions of souls that has come and gone would accept him, he still would have died the same way.
Yes, he will still have mercy on you. Promise.

[ClaecElric4God]

What's already been said. God has shown mercy to people who have spent a lot more than 18 years doing a lot worse things than you have, I guarantee it. And those same people have gone on to be great men and women of God. He doesn't condone it, but He will forgive you, and He will have mercy. It's all throughout the Bible, even in the Old Testament, before the age of grace.

I'm not gonna go into all the "you need counseling and get help" and all that stuff that everyone has already said a dozen times. I'm just gonna answer your question and leave it at that.
Yes, God is that merciful. It's all through the New Testament, go ahead and read it. It'll give you some peace and reading the Bible will be good for you.

[Mr. Rogers]

God will forgive all sins if you are willing to be forgiven. If you have had things in your past that might cause some spiritual difficulties, I might recommend the following book:

Neil Andersen: Steps to Freedom in Christ [http://www.amazon.com/Steps-Freedom-Christ-Step---Step/dp/0830735860/ref=sr_1_1?s=books&ie=UTF8&qid=1385666426&sr=1-1&keywords=neil+anderson+freedom+in+christ]

You are no longer obligated to that old world. You have authority and forgiveness.