I liked your interpretation of this piece, especially the A section. It seemed to flow as Joplin indicated with his extensive ties. With one exception. In measures 10 and 12, the transition between the first two RH chords seems a bit choppy. The first chord sounds stacatto, the second too loud.
Some of the dynamics in the B section aren't those notated. The section is marked forte, transitioning to mp the second bar thereafter, with an mp mark in the bar after that so that the next bar thereafter begins forte again. After that, there are no dynamic marks until the third from the last bar of the section, which is marked mp. This is instead of the cresendoes you use in the phrase with the 16th note ascents to the dotted quarter.
You've added a transposed repeat at the finish, along with an arpegiated final chord. Joplin notated the final chord with an emphasis mark.
All in all, it's definitely Joplin, but, to my ear, with a bit of Debussy arpegiations and tempo variations.
Best regards,
Jim Ritchie
P.S. Yes, it is marked "Mexican Serenade"
jpr