Why does my 7 yr old daughter cry everyday when she gets dropped off at summer camp?

She will be 7 in a couple months and entering into the 2nd grade. She just started at summer camp a week ago & everyday when she gets dropped off she cries. I tell her if she doesn't like it she doesn't have to go but she insists she is having fun and wants to stay. The beginning of the school year is hard on her too. I know she is a shy child but only outside of our house. Should I be worried or is this something she will overcome?