Here are some short 21st birthday poems:

1. "For You" - A day you’ve waited for forever, now you're twenty-one.
2. "A New Beginning" - Life has just begun at 21.
3. "The World Anew" - Celebrate this milestone.
4. "A Memorable Day" - Happy 21st birthday!
5. "A few words, painless and short" - Wishing you health and joy ¹.
6. "The Dawn of Twenty-One" - A new chapter begins ².
7. "Cheers to Twenty-One" - Raise a glass to the stars ².
8. "Flight of the Falcon" - Soar high on wings of twenty-one ².