My son's early reading issues were due to problems with visual processing, tracking, and convergence, with some scotopic sensitivity thrown in for good measure, not dyslexia. There are lots of things that can disrupt reading, many of which can be accommodated or remediated much more easily than dyslexia.
What do her reading errors look/sound like? Does she have a good grasp of phonics, and does she attempt to sound words out? Does she rely on picture cues? Can she sound out words of two or more syllables if they are large and the only word on the page? Does she seem to "get lost" on the page, mixing parts of one word with parts of another word on the same line, or on a line nearby? Does she skip over words? Does she follow the words on the page from left to right with her finger? Does she prefer to read in dim light? Has she ever mentioned that there are colors on a page that isn't printed in colored ink or paper? Is large print easier for her to read than small print? does she read more easily when there is only one line on a page? Does she mistake lowercase b for d or p or q when reading? Looking at what kinds of errors she makes and what strategies she uses to try to help herself can tell you a lot about what is happening to interfere with her reading. Once you have a handle on what is happening, (true dyslexia, visual processing issues, poor phonics instruction, needing glasses for reading, etc.) it will be a lot easier to figure out how to help her.
You might want to search out books that have an "HL" lexile designation, which are designed to appeal to older readers who are reading below grade level - the H stands for "High interest" and the L for "Low lexile" You might also see them described as "Hi-Lo" readers. But pre-read them - some are aimed at kids in grade 7 and beyond, and may deal with more mature themes than you want your 8y.o. engaging with.
