Euro Rail Pass Prices

I have a question about he euro rail (please see the additional info cuz i cant fit it all here)?
I was looking at prices for a 15 day pass and i saw that there was a super saver pass and another pass which said ”
* If you are older than 11 and younger than 26 on the first day of travel, you can buy a Eurail Global Pass Youth, offering you 35% discount on the Eurail Global Pass Adult fare! ”
so that means that i have to buy my ticket once i arrive in europe and can’t buy it online before hand?
if so, is that a problem or risk at all?
Usually they do have a “special price” for students or people thats under 26.So i dont think u wud have a problem but check before hand if the ticket applies to the destinations that ur heading to.All u wud need is ur passport or somethin that proves ur below 26.U can choose to either purchase it online or when u have arrived here.U can get it even at travel agents here,not only online.If not, u can also check eurostar.Good Luck!