Ordinarily this is not possible until you are formally received into the Church - either by baptism or by making the Profession of Faith or what have you. If you are aware of any mortal sins before then, you can certainly seek counselling from a priest but not formal absolution.
However, be at peace. Firstly, say an Act of perfect contrition. Perfect contrition (sorrow for sin that results from love of God rather than fear of hell or other things) also procures the absolution of sins without confession, although the obligation is still there to confess as soon as you are able.
Secondly, rest assured that God does not demand the impossible of us. At this stage you may not be able to receive formal confession but God knows your heart and your sorrow for your sins and I am sure is well-satisfied that you would confess them if able.