My personal opinion on callings... the most important callings in the Church are 1. Primary and 2. youth related callings, (YM or YW related). what else is there besides serving a full time mission that you get to instruct others on gospel truths. Not to put any other calling down, but most others are administrative in nature.
Also, don't worry about how good of job you might do. Please do not stress over it. Callings are a chance to 1. learn and 2. serve.