Schools are not always more expensive for younger kids. In 2014, the Bright Futures top amount was about $3000 per year, didn’t cover required summer sessions. Now it covers full tuition (about $7000), $600 for books, and is available for summer. U of Wyoming’s Rocky Mtn Scholars amounts almost doubled in 2015; lucky us, she started in 2014 and is stuck with those amounts even though tuition is the same for everyone, whether you started in 2014 or 2015.
Some merit scholarships go up, Pell goes up a little each year, schools that give need based aid often increase it if costs rise.