Thank you for your question! I am sorry to hear that you have been ill, and hope that you feel better soon! It sounds as though you have a good idea where your five year old daughter is in the main subject areas. CHC's materials are very self-guiding and I believe that your daughter will have no trouble working independently with them.
There are a couple things that you might particularly like about CHC's lesson plans. For one, the school week is Monday-Tuesday-Thursday-Friday. This gives you the chance to regroup on Wednesday, and either use that day for extra-curricular activities, or valuable time to rest. Also, you will find in CHC's lesson plans, that they conveniently outline all the main subjects: Reading, Math, Religion and Science. The other subjects: Social Studies, Handwriting, Art and P.E. are considered extracurricular. This way, if you are feeling unwell or too tired to teach, your daughter doesn't have to complete all that is listed in the lesson plans, but she will still have covered all core subjects.
Encouraging independency is important for every child as he/she progresses through childhood. You have probably already discovered that your 11 year old daughter can help her sister with her homeschooling. You will probably find the first grade curriculum challenging enough for your daughter. You will probably find that she will progress quickly through some areas, and more slowly in others.
God bless you and your family.