This miniature is a masterful example of late-Romantic and Impressionist lyricism. Its beauty stems from its simplicity and the delicate, evocative color of the melody.
The main challenge is balancing the delicate melody against the harmonic accompaniment with consistent, soft projection.
Comparable difficulty and character — good candidates for what to learn next.
La fille aux cheveux de lin 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 La fille aux cheveux de lin lasts about 2 minutes.
La fille aux cheveux de lin is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Rêverie by Claude Debussy, Berceuse pour 'La tragédie de la mort' by Claude Debussy, Berceuse pour 'La tragédie de la mort', CD 100 by Claude Debussy — see the full similar-pieces list on this page.