Post older female characters attracted to and falling for younger male characters

Sayo from Recorder and Randsel fell for her best friend's little brother - who happens to be an elementary student who looks like a high school student or adult.

Ms. Kazumi from Please Teacher! She falls in love with Kay Kusanagi, one of her students!

Canaria Utara for her childhood friend Ichiya Suzaku from Qualidea Code.
Well, she used to be a year older, but Ichiya was woken up from cold sleep a year before she was, effectively making them the same age.