Mozart's variations on 'Come un agnello' (likely referring to K. 460 or a similar setting) are a charming set that explores a lyrical theme with elegant figuration. They exemplify Mozart's mastery of grace and melodic development.
The focus is on producing a beautiful, singing tone and executing the decorative passages with lightness and clarity.
8 Variations on 'Come un agnello' is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 7.
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 8 Variations on 'Come un agnello' lasts about 8 minutes.
8 Variations on 'Come un agnello' is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.