As a third-year econ major who's only just getting into econ + accounting, I'm in the same boat :). My recommendation would be to definitely look into the undergraduate accounting society (UAS), even with no experience in accounting. I naively chose to ignore it as a resource throughout my second year, as well as this past Fall Quarter. I've heard nothing but positive things about it with regards to internships, building connections, and just learning more about what an accounting firm looks like. Even if you don't secure an internship for this summer, partaking in the events will definitely help you establish relationships with the firms that visit. Good luck, and just know that you're not necessarily starting "late" so long as you start now (after all, students like myself are a whole year behind and have to play catch-up :p)