Originally a popular jazz song by Walter Donaldson, this piece is frequently arranged for solo piano in a stride or novelty style. It is distinctive for its syncopated rhythm and tongue-in-cheek title.
The main technical challenge involves executing the stride-piano rhythmic drive with consistent accuracy.
Comparable difficulty and character — good candidates for what to learn next.
'Tain't No Sin 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 'Tain't No Sin lasts about 3 minutes.
'Tain't No Sin 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 'Tain't No Sin (To Dance Around in Your Bones) by Walter Donaldson, 'Cause I'm in Love by Walter Donaldson, Bach-bwv-anh-114 by Johann Sebastian Bach — see the full similar-pieces list on this page.