It's not known what she's actually studying, however Aya Hirano will be in America for the next six months - not four, as various sources erroneously reported - as per the anime Misa actress's announcement on Instagram:
Good luck to her! Though I can't help thinking that we should be a little more concerned that Death Note's Second Kira is gaining access to the Big Apple.
Shout up, Americans, if you see her there, and do pass on our love.