Is it normal that my step sister is incredibly lazy?

Shes 21 years old and has no desire to do anything with herself. She is the weirdest person ever. she doesnt want to work at all, even the mention of work freaks her out to where she wants to cry. her parents give her money for nothing, and she is interested in childish things. such as anime, winnie the pooh, and hello kitty. she does have some mental health problems...obviously, but shes 21. she can read and write perfectly and she hasnt qualified for SSI checks yet, so why cant she work? She sounds worse than she is, she worked at the good will with her class for awhile and they said she was great. But she doesnt want to go back and wont do anything. She wants everything handed to her and she is quite rude a lot. She will take over everything like she owns it. I think she needs a job and needs to get over wanting everything handed to her. But is it normal for her to act this way?