Hi Karlyn! LHTH is a wonderful start to homeschooling, even with a 4 1/2 yo who knows some of what it has to offer.

I say "some" of what it has to offer because it has a lot more to offer than just colors, shapes, numbers, and ABCs. LHTH is a mini version of LHFHG. It has daily history, covering Biblical history chronologically from Creation to Paul's Missionary Journeys. Each history theme is accompanies with follow-up history projects, art projects, active exploration, and fingerplays. A sound and action is taught for every letter of the alphabet in a very systematic way. All of our dc knew one sound for every letter of the alphabet upon starting phonics, and this made them successful early readers. The devotionals offer wonderful opportunities to have deeper discussions and delve into Godly character qualities. Many more math skills other than counting are covered. Here is a link to the "Introduction" of LHFH, and I think by reading through it you'll see all that LHTH has to offer.
http://www.heartofdakota.com/pdf/little-hands-intro.pdf
As your dd is 4 1/2 yo and knows her colors/shapes/numbers/letters, doing daily history, projects, learning her sounds, and delving into deeper devotional topics will add to her repertoire and prepare her beautifully for LHFHG! If you would like, you can do 2 lessons of LHTH a day, maybe one in the morning, and one in the afternoon, and finish the guide by the time your dd is at least 5 yo. She could then begin LHFHG having been used to a balance of all school subjects, a 1 hour school day addressing each subject area, and be well-prepared for the 1 1/2 hour school day including all subjects in LHFHG. We loved LHTH 3 times with our 3 sons - I think you and your sweet daughter would too! HTH!
In Christ,
Julie