We feel you, as the parent, will always have the best interest of your student at heart. There is no requirement for you to wait until the end of a school year to begin homeschooling. You must do what is best for your child.
You have two primary options to homeschool in Tennessee (there are other schooling options available here.).
1) Enroll with an umbrella school that has a homeshool umbrella option
2) Notify your county Local Education Authority (LEA) that your are withdrawing your student and will homeschool independently- Usually a school system county office person is designated as this roll and will guide you in the requirements.
If you select #1 and you have students currently enrolled in public school, we would recommend you first make arrangements and enroll with an "umbrella school" - which is a term used to define a Category IV Church-Related Private School in the Tennessee Laws. Once you have been accepted by the new school then notify your LEA that your student has been transferred to another school and tell them which one. You want to avoid unnecessary truancy inquires. At that point the new organization will be responsible for records requests or any other documentation, if needed, for the transfer to be complete.
Option 2 for many counties is easy enough, but most if not all will require standardized testing at the periods in line with other students at grade level.
If standardized testing is not a good fit for your situation, we encourage you to find an umbrella that gives you the flexibility to oversee and administer whatever testing you feel can measure appropriate success of your student. Some umbrellas will require the same standardized testing as public schools.