Find out the MAXIMUM are you are required to inform your local officials. DO NOT register your child before that age even if you are homeschooling them. By registering before the required age you are not giving your child a head start your are teaching anyway but you may be PUSHING for a law that FORCES all parents to register earlier than they feel is necessary! 

Your child is NOT behind or ahead of where they should be. Attaching someone else's time table to your child is just going to frustrate you and them. Wait it out!! They will do it when they do and no pushing, pulling, threatening, or pleading is going to make it happen any faster!

That being said goals do help us get where we are going. When we set our goals we used three or four places to decide what we wanted.

First our State (Maine) had standards that we needed to meet. You can find your States Standards here.
Then we found  that there were also National Standards that although similar to Maine's were more specific so we also referred to them in setting our goals.
We also referenced the Course of Study from World Book Encyclopedia which is found on the ABOUT.com web page linked to lessons and Ideas.
Recently we found an OLD book telling us what is taught when. This book is from a time when Highschool was Higher learning the same as College is now.

What Grade is My Child In?
In Maine the youngest grade a child is allowed to enter kindergarten is 5 years old!  Each state may have their own guideline so this is just a ball park range. If you are Home schooling you are required to register at age 7. Therefore, a Student in Kindergarten is between age 5 and 7. This is the basis for my chart. Our Family uses three grades! I have added our levels to the chart. Inside those level you are free to use materials regardless to the grade level on the cover so long as they are working for your child.

GRADE            Youngest    Oldest                                          Oakes Homeschool Level
Kindergarten    5                7                                                  Beginner
1                       6                8                                                 Elementary
2                       7                9                                                 "
3                       8              10                                                 "
4                       9              11                                                 " Possible Middle school if ready
5                       10            12                                                 Middle School
6                       11            13                                                 "                  
7                       12            14                                                 " Start some Highschool Classes if Ready
8                       13            15                                                 " Start Some Highschool Courses if Ready
9                       14            16                                                 Highschool Courses  w/CLEP See our 7 and up
10                    15            17                                                  "
11                    16            18                                                  "
12                    17            19                                                  "