I've just been deferred at my dream school..still bother?

so i've just been deferred at upenn, and this only cements my determination to get in and willing to do anything it takes to become accepted. However, the 10-15 acceptance rate for deferrals is a little daunting. do they defer you because they really think you have a shot? or are they humoring themselves? How do i show them that i REALLY want to attend without annoying the heck out of them?