Hans Christian Lumbye's 'Albertha Vals' is a charming 19th-century Viennese-style waltz. It is characterized by its graceful melodies and lilting rhythm, typical of the genre's popular appeal.
Focus on maintaining a steady, flowing waltz rhythm and a graceful, legato melodic line.
Albertha Vals is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 4.
You should be comfortable at Henle level 4 — meaning you can already play level 3–4 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 Albertha Vals lasts about 3 minutes.
Albertha Vals is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.