Telemann's duets are prime examples of Baroque contrapuntal writing, demanding independence and interplay between the melodic lines. They are valuable for developing aural skills and understanding Baroque stylistic conventions.
Mastering the intricate melodic lines and precise articulation is key to bringing these duets to life.
3 Duets is rated Henle level 3 of 9 — late beginner repertoire, roughly ABRSM grades 4–5. In the RCM system it corresponds to about level 4.
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 Duets is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.