My sims tend to have a de facto drop out option when they go to school for the first week of their child/teen life stage then use their vacation time to skip the second week. From where I'm sitting, toddler/childhood is for getting those skill boost bonuses for later life stages (Top Notch Toddler, the four Gifted traits earned by children, and the skill-rate boost earned from Scouting), and the main goal of my teens is to earn a full ride to college through skill-based scholarships (and get Handiness to level 6 so they can improve the bed in their college dorm to actually get a good night's sleep.)