I know God can forgive any sin, but I've been stuck in porn since I was 11. I just graduated high school and now I'm 18. I feel so ashamed because I wanted to quit the porn and masturbation phase or the sinful life once I turned 18. Every single time I would go forth and sin, I would tell God I'm so sorry afterward. I would tell Him, "No more! This is my last time doing it!" But I would struggle with the same problem again like, 2-3 days later.
My question is, do you have any advice for a young man like myself? I've been reading tips on masturbating in the shower and installing blockers, but I feel as though I can control this habit without precautions such as those. I mean, I'm practically a grown man!
Just because you are an adult, it won't protect you from temptation and sin. I've known many adults in their 30's, 40's and 50's who struggle against pornography. Intentions are usually not enough. The best solution is swallow your pride that demands that you solve your problems only on your terms. "Humble yourselves in the sight of the Lord, and He will lift you up" (James 4:10).
There are two things going on. First, you've trained yourself over the years to use pornography to trigger ejaculations. It is a habit that can be broken, but only if you don't continue to reinforce it. The second thing is that your body needs to ejaculate periodically. I'm guessing that since you rarely last more than 2 or 3 days that you currently need to ejaculate about every other day. But like many guys you try to stop pornography by stopping all ejaculations. That is like solving the problem of eating too much by not eating at all -- it just won't work because something eventually will give and you return to old habits because new ones are not created.
The whole purpose of the Internet filters is not to stop you from looking, but to make it more awkward so that you have time to think instead of letting your body run on instinct. The purpose of using the shower is to establish a habit of ejaculating without access to pictures. Can it be done in other ways? Yes. But the targets still need to be there. Otherwise when you need to ejaculate you'll be back browsing the Internet for porn without much thought.
Notice that is exactly where you are stuck at the moment. You tell yourself no more after this time. There is an infinite number of one more times.