What does the cryptic crossword clue "Sweetly pretty princess growing up: she’s 11 or 12 perhaps (9)" mean?

The wordplay uses a reversal. TWEE (synonym="Sweetly pretty") + REGAN (reversal="a") = TWEENAGER The answer is TWEENAGER.

Sweetly pretty princess growing up: she’s 11 or 12 perhaps (9)

Guardian Cryptic #29638 | 2 Down | 2025-03-10 flower