If a woman lives by herself people might end up talking that she was Mezaneh -whether true or not.
If she lives with others (roomies, parents, etc.) that is excluded? From the Lashon of the Rema (Ta’amod B’lo Ish), as well as the Rambam in Hilchois Issurei Biah, it would seem that is OK (certainly with a parent).
Also, being that it is a machlokes HaPoskim, I don’t think you will find any Rov who will say a girl has to marry. (Of course, if one is the such that in general is Machmir, they can do so as well here).