As an organist, I don't know much about Mozart and I seriously lack of classical-classical experiences (I mean for ex. not classical-baroque, and not classical-romantic, but classical-classical), but from the Mozart pieces I've heard through my life, your piece has some really Mozart-y sounding parts for sure.
Particularly my favorite parts are which I think they sound the most Mozart-y,
around 0:03 "Di - Re" ("C# - D" in your piece's key), and around 0:09 the "Ri - Mi" ("D# - E" in your piece).
I think this type of half-step (most of the time from bottom to the top(?) I mean stepping up a half-step we could call it one of Mozart's signature pitch-writing.
As a mini-tip: I think you can do this half-step-up-melody-trick on almost any note, except "Li - Ti" ("A# - B" in C major key), because "A#" or "Bb" however we call it at the place of the context in C major key most likely it would sound like the "Fa" note of F major key, it would sound like the "Tay" note of C dominant chord, and "Fa usually want's to go a half-step down, instead of down, at least in the case of a C dominant 7 chord, if you would play for ex. a C dominant 7 chord and then a G or a G dominant 7 chord to force the A# go half step up to B, then I think it would not sound right in a classical-classical context, it would sound almost like a certain part of a blues chord progression especially if we would chose to use only dominant 7 chords.
Probably I wrote this explanation unneseseraliy complicated and too long, sorry about that 🙂 It's not that important,
but in an easier way I could say that my tip is that I think you can do these half-step-Mozart-y-pitch-writing:
C# - D
D# - E
E -F
(probably even F - F#)
F# -G
G# - A
(but CAN'T do A# - B)
B - C too I guess
I can't explain well why I think this, this is just my intuition, probably I'm wrong somewhere, others might tell us where.
Another little thing is that I think the Alberti-bass was a good choice to start with, I think Mozart liked to use it a lot!
As I wrote earlier I don't know much about Mozart, but these are the things that I've noticed immediately even by not knowing Mozart too much so you made even me recognize the essence of Mozart in your piece, so I think you are on the right track!