Cramer's Op. 4 sonatas showcase the clarity and grace of the Classical style, often featuring well-defined melodic lines and balanced phrase structures.
Focus on clean articulation and evenness in scales and arpeggios.
3 Piano Sonatas (Op.4) is rated Henle level 3 of 9 — late beginner repertoire, roughly ABRSM grades 4–5. In the RCM system it corresponds to about level 3.
You should be comfortable at Henle level 3 — meaning you can already play level 2–3 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
3 Piano Sonatas (Op.4) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.