a prosecutor said that jamie silvonek , 14 , accused of conspiring with her soldier boyfriend to kill her mom should remain in an adult jail .
her boyfriend , 20-year-old caleb barnes , who is from el paso , texas , but was stationed at fort meade , maryland , is charged with homicide .
cheryl silvonek 's body was found stabbed in a shallow grave about 50 miles northwest of philadelphia .
` she threatened to throw me out of the house . i want her gone . ... ` just do it , ' silvonek allegedly texted barnes before the killing .