Help! Trying to reconcile two competing philosophies?

Sorry, my long-delayed Teen Angst is suddenly kicking in in full force. Please bear with me.

What do you do when you're at war with yourself? My mind says full speed ahead, knowledge is key, but my heart is telling me to hold back and enjoy the moment while I still can. I'm not sure whether I'd prefer to succeed in the future at the cost of the present or whether I want to be happy now at the cost of the future. After all, what is all the wealth of the world without someone to share it with, but what use is all the pleasure of a moment after the moment is gone? I'm just really confused and conflicted right now.

For most of my life, I've scorned the silly childhood diversions that so many others seemed to delight in as a waste of time, but now I find myself longing to redo it all and squeeze everything I can from my vanishing childhood. This is my last year of high school, and what comes next? Four to eight years of college work, followed by a lifetime of hard work in a probably boring job with little or no time for what little fun I used to enjoy? I don't have time to pause and reflect, but I can't help but stop and wonder what life could have been if I had taken the time to enjoy myself. Now it's almost too late, and I find myself seriously considering going out in a blaze of hedonistic fatalism. Please; if you have anything you can say that might help me, one way or the other, say it now.