The ability to engage task control flexibly, especially in anticipation of task demands, is beneficial when juggling different tasks. We investigated whether children in late childhood or early adolescence engaged preparatory task control similar to adults in a trial-wise cued task-switching paradigm. Twenty-eight children (aged 9-15 years) and 30 adults (aged 21-30 years) participated in an fMRI study in which the Cue (preparatory) period across 2 tasks was analyzed separately from the execution of the tasks (the Target period). Children performed more slowly and less accurately than adults, and showed behavioral improvement within the child group age range of 9-15 years. Children exhibited weaker Cue period activation than adults within a number of putative cognitive control regions. In contrast, children exhibited greater activity than adults in several regions, including sensorimotor areas, during the Target period. Children who activated cognitive control-related regions more during the Cue period tended to activate the Target signal age-related regions less, and this correlated with improved accuracy and reaction time on the task, as well as age. The results endorse previous findings that preparatory cognitive control systems are still developing in late childhood, but add new evidence of age-related shifts in activity at the trial level.