Ten year old getting a teenage attitude

My 10 year old is starting to show signs she's going to be a teenager soon. Sassy, talking back, questioning everything...any recommendations?

    Lay down the law now? My sister and brother in law were going through this.. When they started homeschooling the oldest the back talking and sassy attitude stopped-like she was learning it from her friends.. My 9 year old has started this and is driving everyone insane.
    About Shelly
    Current: Virginia Beach, Virginia
    Birth: November 26
    On Moms.com since: Nov 30, 2013
    A stepmother and am hoping to get pregnant soon.