Clue: Queen Victoria's beginning to interrupt all her children, quelling excitement? (7)
Answer: NERVINE
Explanation: Definition: quelling excitement?
**ER** (Elizabeth Regina, so "queen") + **V**(ictoria) [*'s beginning*] *to interrupt* **NINE** (the number of "children" she had) 
 
 
*A nervine is a nerve tonic, often herbal, taken to "calm ruffled nerves"