High School achievements in Spring Week Resume?

I'm a first year in a top business school in Sweden and I'm interested in applying for spring weeks in order to maximize my chances to land a summer internship next year. The question is, as I haven't even barely started studying for real yet as a first year, that means I don't have any university extra-curriculars right now as the uni-year hasn't started yet. By the time applications close in novemeber/december I'm sure I will be able to mention something from university, but nothing spectacular as I only would have a couple of months to achieve something worth mentioning. 

Which brings me to my question - I have lots of achievements I can bring up from high school, but is that even relevant? Do they care or do they not give a shit about things you did in HS? Just trying to figure out how to come up with the best possible resumé and cover letter.