why is student offer only available for 18

I am 17 years old and am studying for my A Levels at sixth form college. My brother is 18 Years old studying for his degree at university. I would say we are both 'Students'. Collins Dictionary agrees, describes a student as someone studying at university or college. However, Apple doesn't seem to think we are both the same. In fact, my brother, who has 18 hours of official lectures/week (none of which he has to attend at the moment), has a part time job, and therefore earning money, and is afforded, by Apple, more and greater offers and discounts, than myself. I am full time education, therefore have less opportunity to get a part time job and therefore, by definition, more in need of offers and discounts. I am an Apple advocate, I have a MacBook and an iPhone and am looking to purchase an iPad to support my studies. But my brother gets a better deal. Yes I can buy it through my brother, but why should I have to. Apple's marketing strategy is unfair. When on chat, the colleague simply said, this is a worldwide offer? does that make it fair? Also, it asks you to verify through UniDays. My brother studies in Edinburgh and there are Scottish students at University studying for degrees with a UniDays account that can get the student offers at Apple? This seems incredibly unfair and biased. Sorry, just a moan as It has made me lose faith a little with Apple.