Women's names back then tended to be short (mostly two-syllable long and sometimes just one as OP's example) and surprisingly simple compared to their present-day counterparts. Baby girls were often named literally after simple plant, flower and animal names, such as まつ(pine)、きく(crysanthemum)、うめ(plum)、とら(tiger)、かめ(turtle)、たつ(dragon), etc. They were by and large written in kana as well because people selected these names for their sounds, not for their meanings.

These names just sounded "better", "cuter" and/or "more rhythmical" if the honorific 「お」 was added. This 「お」 was for expressing affection, not necessarily respect.

「さん」 was also added depending on who was addressing (or referring to) whom.