can a mother get charged with kidnapping if she dont have custody

If you both live under the same roof you can take care of your six-year-old.  However, if you move out, the father has custody and the vistitation set forth in the order is the schedule that you will have to follow, until such time as you file a Motion to Modify Custody and demonstrate a material change since the last order was entered.  You can ask for custody and demonstrate that you have been the one taking care of the child.  Look at Virginia Code Section 20-124.3 to see the factors a court must consider when making a custody determination.