Schubert's "11 Ländler in B-flat major" D.374 are delightful short pieces that embody the spirit of Viennese folk dances. They are characterized by their graceful melodies, simple harmonies, and characteristic triple meter rhythms.
Mastering the characteristic Ländler rhythm and maintaining a light, elegant touch are crucial.
11 Ländler in B-flat major (D.374) is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 6.
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.
11 Ländler in B-flat major (D.374) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.