Hope someone can help me with this "small" problem.

I have found a distant relative in 1871 in what looks like,Nunnery ,Mount ?,West Derby,Liverpool,
Ellen Theresa Feeny,born 1854,Liverpool.
RG10/3841,District 12,pages 14-18,
The head of the page gives a Sister of Mercy.
It looks like she may have taken Holy Orders,and became a Nun,or was this a Mother to be home.
What if any records would be available and were would I look.
I cannot find her after 1871,and wonder what name she would have taken.
Many thanks Tsumi