“Is tonsillitis serious in kids?”

Yes, the child should get Tonsillectomy by age 9-12 y.o. or when cleared best over 5 y.o.

Tonsillitis is generally limited to a fairly severe sore throat that persists for days. That being said, there are numerous complications that can occur. So, discuss the severity and frequency of these infections with your daughter's pediatrician and consider a referral to an otolaryngologist.