Johann Georg Lang's piece is a compact Classical movement that emphasizes clarity and rhythmic drive. It is a rare example of 18th-century keyboard work that retains a sharp, witty character.
Technical proficiency in executing small, rapid turns and clean articulation is required.
Comparable difficulty and character — good candidates for what to learn next.
Allegretto in A major is rated Henle level 3 of 9 — late beginner repertoire, roughly ABRSM grades 4–5. In the RCM system it corresponds to about level 4.
You should be comfortable at Henle level 3 — meaning you can already play level 2–3 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Allegretto in A major lasts about 2 minutes.
Allegretto in A major is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Piano Sonata No. 16 in C major by Wolfgang Amadeus Mozart, Alla Turca by Anton Diabelli, Alegretto by Franz Schubert — see the full similar-pieces list on this page.