My 2 cents:
Keep working on it until she gets it! But, don't worry!
I have good friends who have homeschooled all five of their boys. The oldest is 22, then 20, then 18, almost 16, almost 9. The oldest graduated from college at 20 with a degree in accounting, had his CPA by 21 and now has a good-paying, stable accounting job. The second will graduate this May with a major in trombone performance and a minor in accounting. Next year he will work on (and probably finish) a master's degree in accounting. Then he will work on his CPA. The 18 year old (who is really the "theme" of my post) is going to West Point in June. The 16 year old and 9 year old are great too, but they're not "finished" yet.
The third-born, that I mentioned is going to West Point in June, was still having trouble identifying all of his LETTERS correctly at age 6. He wasn't a good reader until almost age 8. After that, because his Mom continued to work gently with him and he enjoyed all of the books that she read aloud to him, he became a voracious reader. Before high school, he read almost all of the G.A. Henty books that he could get his hands on. He read LOTS of biographies, lots of "good, classic, twaddle-free" literature. (However, I think, in some aspects, his parents are even "pickier" than Carrie about making sure that what he read was age-appropriate and would encourage good thoughts. They also didn't allow much, if any, fantasy-type literature.) When he hit high school, other than certain literature they had him read, they really switched gears to having read mostly non-fiction. He has read an AMAZING number of thought-provoking books. He also spent a LOT of time reading the Bible. (I can't remember off-hand how many times he read through the whole thing in high school, but it was A LOT. He also has memorized several books of the Bible: James, some of the shorter epistles, several chapters of Proverbs,etc.) Anyway, this was from someone who was at "emerging reader" level at age 8. Oh and this year, in addition taking second year Spanish and Calculus at the local community college (as a senior in high school), he also finished both Advanced Chemistry and Advanced Physics from Apologia (the SECOND year courses, not the regular ones) and got flying colors on the AP tests. He also scored really well on both the SAT and the ACT.
So, while there MAY be a problem, I would say for now, keep plugging along and read to her A LOT. We have known our friends for about 12 years. So, I can remember when Jason couldn't even read and have watched the transformation. I have also seen the "success" they have had with the way they have handled many situations. And they are definitely "less is more" homeschoolers. I don't think ANY of their kids did more than 3-4 hours per school a day until they were well into high school (and that was only because then they were doing online college classes and classes at the community college for dual credit).
My advice is don't compare. Just keep on keeping on.
(And this comes from a Mom who has had a child read at 4, one at 3, and has an almost five year old who may or may not be reading well by the time they are six.)
We end the day reading in bed together too, which is normally less strict & more fun, where I give her the word right away, if she is stumbling, & she really likes that. 
