Reflecting on the preciousness of this life is intimately connected with the second mind changing: life is to be met with sacredness as it is so beautifully and poignantly fleeting. I imagine that contemplating impermanence when you are so young, with expectations of so much ahead will be challenging as even most adults need a crisis to reflect on the unpredictable aspects of life.
In Buddhism one allows this invisible instigator of preciousness to function as a catalyst for developing vivid awareness, for cultivating the ability to ride the flow of change fluidly, knowing nothing in this world stays the same.
Contemplate your own ever changing metamorphosis by observing all your dynamically changing feelings in one day. Start now, being aware of how you are feeling just this moment and see if you can detect when this feeling changes and becomes another feeling. At the end of the day reflect back on this moment and retrace all the changing feelings you had in one day!