By definition, Header Rows are at the "head" (top) of the table. They contain information about the content of the Body Rows below. So that is not possible in any version of InDesign.
You could create a row across the middle of a table where text extends across all the cells if you selected that row and chose Table > Merge Cells.
Maybe you need to repeat header row in another page or text frame. If is that what you need, there's a solution to that.
1. DUPLICATE your top row;
2. Convert first (only the first one) top to header (RIGHT CLICK -> CONVERT TO HEADER ROWS);
3. Open table options (RIGHT CLICK -> TABLE OPTIONS -> HEADERS AND FOOTERS);
4. In the Header field choose Repeat Header in Every Text Column and mark Skip First option.
Yout table header will apear in every text fields until your table is over.