Answer
As salamu ‘alaykum and may all your good intentions bear fruit, insha-Allah.
It is not common for someone of your age to take a back seat and reflect on ones lifestyle, and then to act according to what is beneficial. My daughter, you are to be commended for your strength of courage and steadfastness in your decision. It is far more common for many people, both young and old to unknowingly have their imagination, creativity, and self-concept held to ransom by modern forms of entertainment. Because modern forms of entertainment are audio-visual, they are very persuasive this is the most effective form of learning.
Instead, many of those entertained by it are slowly lulled into seeing, feeling, and understanding as the modern modes of entertainment would have us believe. We mistakenly allow ourselves to believe that those ideas, identities and lifestyles expressed are what we want – are our own not realizing that we have relinquished our right to choose to these modes of entertainment. We even lose sight on how monotonous these subliminal messages have become.
A young person like yourself is more free to understand their own selves, and to develop their own imagination, creativity, and identity away from these forms of entertainment that you speak of. They are more able to identify their own feelings, their own concerns, are more receptive to those around them, especially family members. In other words, there is less of a barrier between you and the real world, and therefore, one is more likely to find ones place in the world.
All said and done, reading feeds rather than hijacks the imagination, and ones identity. The variety of subjects and issues are broader, and their is space for ones own thoughts and feelings. If this space did not exist, you would be less able to reflect on what you have been reading, and to identify something as being haram.
The only problem we are left with then is what you choose to read. Given the description of what you do read, entertaining though it may be, there is little difference in approach to a subject matter than the very media you are trying to avoid my daughter! You say you like to read romantic novels, thrillers, and anything that interests you. If you put aside the romantic novels and the thrillers, what are you left with amongst your other interests? Assuming that there is nothing haram in your other interests, add to it a whole ocean of subjects and issues to explore, and you will find that you have a very interesting time ahead.
One can resort to libraries, but depending on the library, you might not find what you are looking for. There are some very good Islamic bookstores, and second hand bookshops, where one can find a wealth of material, and save some in the process. Depending on the type of second hand bookstore that is available to you, you can even return what you have read, get a refund, and buy another book.
At the same time, life is not about books, that is why in Islam, knowledge is only useful when it is put into practice. So besides reading, think of activities that interest you where you can meet like-minded girls, especially in Islamic settings. In this way you share your interests with your peers, as well as develop needed social skills that can prevent you from becoming too introverted insha-Allah.
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