Dorothea Lange, "Woman aged 70 from Nebraska", Kern County, California, 1940 (Wikimedia Commons, public domain)
Primary sources that have been edited, reprinted in facsimiles, or transferred to microfilm can be borrowed through E Z Borrow or interlibrary loan if they are not in Tripod. Many of them will be listed in Tripod and WorldCat under subject terms which include such words as "sources," "letters," "diaries," or "personal narratives." For example, the search (aged OR elderly OR seniors OR older OR aging) (sources OR diaries OR "personal narratives" OR correspondence OR anecdotes) produces results including:
Nobody's home : candid reflections of a nursing home aide
Author: Gass, Thomas Edward.; Vladeck, Bruce C. Publication: ILR Press, 2004
At eighty-two : a journal
Author: Sarton, May, Publication: W.W. Norton, 1996
The New York University School of Medicine has created a database of literature and the arts with references to medical conditions. This material gives you a first-person point of view of the various ailments that older people develop.