We are sure your next three weeks are absolutely packed with activities, or you would have waited to make the pastry shells till the last minute, knowing, as you do, that they are such a wonderful treat fresh, and not as special after waiting around for three days or three weeks. Alternatively, you would have piped or scooped or molded them and frozen them before baking, to be popped into the oven at the last minute, if you had had the opportunity.
But, as cooking often includes compromise, you now find yourself wrapping them carefully in plastic to protect them from condensation and freezing them. As the appointed day arrives, you will thaw them without unwrapping them (to forestall condensation), gently unwrap them once they reach room temperature, and crisp them in the oven briefly before serving. And your guests will be so thrilled to have home-made pastries instead of margarine/vegetable shortening-based store-bought, that no one will even suspect that they spent time on ice.