This is a lighthearted pedagogical piece intended to evoke a festive atmosphere. It uses simple harmonic patterns and accessible motifs.
Emphasize clear articulation of the short staccato passages.
Comparable difficulty and character — good candidates for what to learn next.
Birthday Party is rated Henle level 2 of 9 — beginner repertoire, roughly ABRSM grades 2–3. In the RCM system it corresponds to about level 2.
You should be comfortable at Henle level 2 — meaning you can already play level 1–2 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 Birthday Party lasts about 1 minute.
Birthday Party 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 Calling by Cheng-Shiun Li, Blumenwalzer by Léon Jessel, Bluin' the Blues by Henry Ragas — see the full similar-pieces list on this page.