I interpreted the first eight measures of the piece as kind of an introduction to the bigger, middle section, arriving at measure 9. The half cadence in the 8th measure drives the beginning of it. this next section is 10 measures long, which feels slightly asymmetrical. in measure 9, a similar melody from the introduction is heard, but the rhythm is different (there are no 16th note triplets until measure 14). a half cadence arrives in the 12th measure of the piece, and the listener craves a PAC 4 measures later. but the melody changes slightly, integrating a new rhythm and a harmonic goal not 4, but 6 measures later. maybe the melody was extended to increase the anticipation of the listener.
after the middle section repeats, the mood changes. the style is no longer marcato but very legato. the last phrase is both parallel and symmetrical.