Behavioral issues in 4 yr old. I do?

Hi, my child is 4 yrs and 1 month old and going to lkg since 3 days, she had normal milestones but her speech is a little hard to understand by others. Today the school principal called me and told child is having behavioral issues, that she doesnt act to her age. she screams in class She use force to resist teachers She pulls hair and hits other kids Never sit in place She is inly o e who walks around in school assembly Spits in class Turns the chair around and stand on table Tells everyone that she doesnt like them. These are the complaints they told in 4 days.. when i suggested she will get better with time, they told they are seeing kids for last 35 yrs and they know if something is not right, and they insisted there is something wrong. What should i do?