This page provides the texts in English medium difficulty. Read a couple of texts:
If the text you are not very clear and there are many unfamiliar words, I recommend first to read easier texts.
If the texts are understandable, but there are unfamiliar words (but not too often), then that's fine. Keep reading and learn all the unfamiliar words. It is enough to increase your vocabulary before you move to the next level of complexity. For a good result, for example, or for a variety of read dialogue at the same level of complexity.
If the texts are clear and unfamiliar words almost do not occur, then you should immediately move to the next level of complexity.