This is a lesser-known but delightful 'Allegro assai' by Mozart, likely an early or incomplete work. It exhibits the composer's signature clarity and effervescence, with cheerful melodic lines and a light, transparent texture.
Focus on a light touch and precise articulation to bring out the playful character.
Allegro assai in B-flat major (K.Anh.95) is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7.
You should be comfortable at Henle level 5 — meaning you can already play level 4–5 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
Allegro assai in B-flat major (K.Anh.95) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.