Having taught some for this exam,I found out , what some of the most popular pieces are.
Blake: Toccatina, fast and exciting, not too hard.Chaconne:ok
Debussy:La plus que lente.Elegant waltz, bit tricky to read perhaps, but not difficult.
Gershwin, only the 2nd Prelude is easy, the other two challenging, especially for small hands., but very exciting stuff.
Brahms: Intermezzo in A, op.118 no 3
Chopin Nocturne in E, op.62/2
Faure:Impromptu in F min, very fast and exciting, challenging.
Ravel:Sonatina.Technically challenging, interlocking hands. But great music.
Copland: Scherzo. Crazy piece, very descriptive. Very popular.
If you absolutely want Beethoven, try Sonata op.10 no2, but you need a reasonably sized hand for 1st mov.
Otherwise I suggest Haydn Variations in F min. or
Mozart Variations: Unser dummer Pobel Meint.
Not many play those last two, I think.
By the way, this is not an easy exam to pass, especially watch out for the quick learning test.
Good luck.