I'm sorry and you all may find my solution to this problem not to your liking. Controversial even.
Don't stress about it - if she does it- fine! If she doesn't - fine! It is not like she is going to fail or fall behind.
I don't think 4,5,and 6 year olds should have homework. I even find 7 a little to young for homework. Why should they do homework - they are babies. They have ahead of them 10-15 years of homework and a lifetime of work. Let them be kids and find things out about the world on there own. (At 13 & 15 my sons have atleast 2 hours of homework a night, so there is plenty of time for homework later.)
Sure you can make things educational but first make them fun. Count the flatware out of the draw when laying the table for dinner. Have magnetic letters on the fridge and play games with them - find me a 's', spell cat, etc. I have always had crayons and colored pencil and paper on the table - they can draw, colour or write whenever they want too. My 10 and 8 year old sons will sit there ages creating things (they both have always liked coloring and drawing). My 15 and 13 year old sons rarely ever touch it when they were little. My 15 year old son liked puzzles when he was little - he now has a very logical mind - that was his strength, but could we get him to write - no! My 13 year old likes sports and is very sociable and always has is head in a book.
Remember always try to read to your children. Plus let your children see you reading a book. Studies have shown that parents who read books regularly have children who read and enjoy reading.
I quess what I am saying is let her find what she likes to do. Don't stress about it. Give her the opportunity to do the work, but don't force it. You never know she may follow her sister's example one day. Find her strengths and let her fly. There will be plenty homework when she's older.