Greetings LaBelleDamesansPatience:
I thought this link to ORT reading levels/ age levels might help: www.oup.com/oxed/primary/oxfordreadingtree/chart/
If you were reading Kipper & Chip - The Ice City - it's level 5 (which is top level reading equivalent ages 5-6 - so year 1).
If that's correct - first don't panic. My DD1 was at this level in Y2 and not much past it at start of Y3 and she's made brilliant progress since then (with a lot of help both at home & at school). For us it was a case of establishing a firm habit of reading, and not letting DD1 come up with some clever excuse about why she didn't want to read.
I think those posting already are right to be asking what precisely do you mean by 'struggling reader'? Is that that your DD doesn't like reading so it's a struggle for you and her to do? Is it that your DD is slow to develop phonetic skills or is there some underlying learning difficulty? You need to arrange to discuss this more with the teacher before the end of the school year, if you are not clear what the problem is. Often dyslexic children can get very adept at memorizing quickly and using picture clues to work out what is on the page rather than actual reading, but when the transition is made to more complicated reading these strategies no longer work as well. Your DD may be mentioning things like the words 'dance on the page', 'the letters move about' or she may be mixing up letters/ words as she reads. Again, I think you should be talking to the teacher/ school about what you can do to support reading at home and help work on this over the summer.
You said she was home-schooled. Did you teach 'look and say' type reading or did you teach sounding out letters and combined letters (blended sounds)? She may be missing some of those early phonetic skills - so perhaps a review with something like Jolly phonics workbooks might also help.
A useful thing to do would be to look at book lists for ages 4 - 7 (sometimes 5-7). You must be aware that some books in this bracket will be a stretch, but you can avoid difficult bits by reading those out loud yourself - or by working through them together slowly.
The guardian lists books for ages 4 - 7 here: www.guardian.co.uk/books/2000/apr/08/childrens.library.47
The Book trust lists books for ages 5- 8 here: www.booktrust.org.uk/books-and-reading/children/booklists/ - click book finder on menu list at left - you'll then get icons for age groups and select 5 - 8. You can then select type of book and then individual books can be clicked. It gives you the reading age under the picture of the cover = which is a useful guide.
Finally I will say this - in many countries children do not start school until the year they turn 7. In many cases children are not reading much at all before they start school - yet they turn out perfectly fine. So don't be too hard on yourself - you haven't 'missed the boat' and there is still plenty of time. So GOOD FOR YOU for realizing something needs to be done and asking for help - that's a great start!
HTH