Answer:
Mi hermana es hermosa. Ella es alta y delgada. Es una muy buena estudiante y es la mejor de su clase. Es divertida y su cabello es largo y rubio. Ella es mayor que yo.
This time we are using Present Simple. We use it to describe a habit, routine or something that happens now. 
When it comes to the verb SER, unlike English where we use the verb "to be" as SER or ESTAR, in Spanish they have different meanings. 
SER describes appearances, identity, family relationships, when and where an event takes place, time and date. 
ESTAR expresses a mood or health status, an aspect, the marital status of a person, their location. 
The ways to conjugate each verb for different people of the present is as follows: 
 
SER: 
yo soy 
tú eres 
él/ella es 
nosotros somos 
ellos son 
 
ESTAR: 
yo estoy 
tú estás 
él/ella está 
nosotros estamos 
ellos están