Sometimes you can get stuck in a little cycle of focusing so much on the past that you forget where you should be heading. At other times, you forge ahead but conveniently forget the life lessons you've learned from your past -- this life's lessons, and those of your past lives in general. After all, even though you don't have a conscious memory of past lives, the information is still in your psyche, and is actually available to you if you use the right methods to get at it.
As a young person you may swing back and forth between the two extremes, showing two distinct modes of mental orientation. The key for you is to find the balance between the past and the future by focusing mostly on the present and letting everything else take care of itself. If you do everything in the best possible way you can today, using what you've learned from past experiences, your future will take care of itself with very little effort from you. This is the best way to guarantee a positive future for yourself.