Instructions
Start the "Sims 2" game. Select your family.
Press "Ctrl-Shift-C". Type "moveobjects on" in the text box that appears. Save the game.
Select "Buy Mode." Select the Sims you want to age.
Turn on "Free Will" in the "Options Bar." Click on the "fast forward" button. The Sims will go about their lives and age faster. When your teenage Sims reach your desired ages, save the game.
Enter "Neighborhood" mode. Click on your Sims' house. Continue playing the game as normal.