Congratulations to her indeed.
The Galaxy is PGC018299, aka UGC3378 way North at +83 deg.
The 17th magnitude supernova is cataloged 2010lt and is a sub luminous type 1a event (merging of 2 equal mass white dwarf stars).
If I remember correctly the previous youngest discovery was a 11 or 12 year old girl and her discovery gained a lot of interest as it too was a sub luminous SN.
More can be found at these sites.
http://www.rochesterastronomy.org/snimages/
http://www.nature.com/nature/journal...ture08642.html
PeterM.