<p>And i.m.o., Steve Jobs said it just as beautifully. 
No, seriously, ADad makes a good point, and the calligraphy should reflect & reveal the writer-applicant, not vice-versa.</p>
<p>My own passion for calligraphy developed toward the end of college and just after. (I later become skilled in both English & Hebrew calligraphy & did both professionally.) I was actually taught by one of the masters in the field who later went on to become famous in graphics. It is extremely time-consuming to excel in it, as it demands a level of perfection that most people are impatient with. So, kudos to OP’s D for making time in her undoubtedly over-busy h.s. schedule. (My own schedule at that time would have been too insane to allow for this careful & contemplative activity.) And yes, passions are associated with it, develop from it. In mine, it was an interest in learning another language as well (not just its alphabet), plus eventually its culture & religion. In others – such as Jobs and my master teacher – it could be graphics, typefaces, & design. Those who become accomplished at Spencerian script might develop a passion for that period of history on both sides of the Atlantic. </p>
<p>The discussion of it in the application, then, should focus on what in calligraphy drew the applicant to it, which could be many things – on why it continues to fascinate & provide satisfaction. It would certainly not hurt to culminate the ‘discussion’ with a calligraphic flourish.;)</p>