This is a miniature mazurka! One of the characteristic mazurka rhythms is a dotted eighth/sixteenth note on the first beat of a 3/4 measure, and we see that rhythm consistently here.
For Chopin, the marking Andantino suggested a tempo slightly faster than Andante. However, it is worth noting that in the manuscript Chopin appears to have written Andante originally. He then crossed it out and wrote Andantino instead. It may be valid, therefore, to perform this prelude on the slower side of Andantino, in recognition of Chopin’s original impulse. Note that the two long phrases in this prelude comprise eight phrase segments of identical rhythm. Could this repetitive rhythm have inspired Chopin, either consciously or unconsciously, to experiment in the following prelude (No. 8) with absolutely no rhythmic differentiation between beats, over 32 measures?
Given that this is one of the shortest works that Chopin ever composed, it is worth considering here the nature of Chopin’s genius for brevity. One essential characteristic of this genius is the knowledge of what to leave out. For an imagination as fertile as Chopin’s, this is no small matter. There is an amusing illustration of this phenomenon in the literary world. The French mathematician and philosopher Blaise Pascal once wrote an exceptionally long letter to a friend, at the end of which he apologized because he didn’t have time to write a shorter one!