I am a 20 year old lady, and I have this problem of constantly clicking on 'inappropriate images' and when I'm done, I feel bad and ask for Forgiveness, but it's become so repetitive! How do I remove sexual desire from within (just until marriage)? I don't even talk to the opposite sex, but what I'm doing is still not good.
There is no way to remove sexual desire. Fasting might help reduce it. The best solution is to reduce your opportunities for engaging in that, such as by only using your computer (if that is what you are using) in a public place, or not spending time alone at home.
At 20 years of age your brain has not fully developed and your power to control your impulses is weak compared to a 25-year-old. There are millions of others like you who wish to stop looking at such things but cannot because of their low impulse control until they get older. For now, don’t lose hope and make sure to carry out all of the obligatory acts Islam asks of you, and ask for God’s forgiveness every time you pray. Meanwhile, try to always come up with new ways of reducing your opportunities for engaging in that, by socializing, finding work outside, etc, and inshaAllah as you mature, it will become easier for you to control your impulses.