Picture what the scene must have looked like. Moshe tells the Bnei Yisroel everyone that is twenty years old and up should bring a machtzis hashekel to be counted. These coins are going to be used for the foundation of the mishkan. Do we have a concept of what it means to contribute to the very yesod of the mishkan. Chazal tells us that had the goyim understood the benefit the mikdash brought to the world they would never have destroyed it. And here you have an individual who has the opportunity to contribute to the very foundation of this edifice. Off to the side is Moshe. Moshe is 19 years old. He was hoping to contribute a Machtzis Hashekel, but alas he is too young. Imagine how devastated he is. Fast forward the Meraglim come home and Hashem issues a decree everyone from 20 years and up will not enter into Eretz Yisroel. Moshe breathes a sigh of relief. He was saved from this terrible gezairah. There are times throughout our lives where we see someone who has something that we don't have. It may even be what appears to be a spiritual achievement that someone else has that we don't. One never knows the price tag that comes along with it. We say in davening "Visen Chelkaynu B'torahsecha." Give us our chelek in Torah. We each have a unique mission. Don't lose out on your own opportunity because you feel like you haven't lived up to someone else's.