A Muslim woman is only obliged to cover herself within the presence of stranger men. She does not have to do it while she is in home with other women or with her father, brothers, uncles or father in law.
Allah the Almighty commands:
“Tell the believing women to reduce some of their looks, and cover their private parts. Tell them not to uncover their beauty except what is naturally seen. Tell them to put their headscarves onto their chests and not expose their beautiful parts except to their husbands, their fathers, their husbands’ fathers, their sons, their husbands’ sons, their brothers, their brothers’ sons, their sisters’ sons, their women, those in their possession, those male attendants that have no sexual desire to women, or children who are not yet aware of the private aspects of women (…)“ (An-Noor/ The Light 24:31)