This piece is a modest Romantic parlor song arrangement for solo piano. Its distinctiveness lies in its simple, flowing melodic line that evokes sentimental Victorian-era salon music.
The primary challenge is maintaining a singing tone in the right hand while managing the gentle accompaniment in the left.
Comparable difficulty and character — good candidates for what to learn next.
'Twas in the Time of Roses is rated Henle level 2 of 9 — beginner repertoire, roughly ABRSM grades 2–3. In the RCM system it corresponds to about level 3.
You should be comfortable at Henle level 2 — meaning you can already play level 1–2 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 'Twas in the Time of Roses lasts about 3 minutes.
'Twas in the Time of Roses 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 'O sole mio by Eduardo Di Capua, Believe Me, If All those Endearing Young Charms by Irish Folk Music, Broadway Melody by Nacio Herb Brown — see the full similar-pieces list on this page.