Reception history simply means what did people think about the opera over time. There are a few key resources you can use to discover how society reacted to a musical work.
Composer biographies often include fairly extensive information about the immediate context surrounding the creating of an opera - where was the composer living, who and what were the influencers in the composer's life at that time, what were the major personal, social, cultural, political events affecting the composer, etc.
Pro Tip - since time is a luxury at this point, only read the portions of the biography that relate specifically to your opera. Discover your target pages by going straight to the index at the back of the book and looking up your opera.
Contemporary newspapers and music periodicals are the best resources for "eye-witness" accounts of how a work was received.