https://books.google.com/books?id=g3RNCAAAQBAJ&pg=PT302&lpg... claims Mary was christened on 11 June 1557, daughter of Robert Taylor, alderman of London & his wife Elizabeth Hatton.
The IPM of Richard Brooke, 1st husband of Taylor's second wife, Anne, taken 1566, notes:
All the said premises are held of the Queen in free burgage, and are worth altogether £5. Richard Brooke died 25 September, 1563; Elizabeth Brooke, Mary Brooke, Anne Brooke, and Dorothy Brooke are his daughters and and coheirs: the said Elizabeth is aged 10 years and more, "the said Mary 8 years," the said Anne 5 years, and the said Dorothy 3 years and more.
(The Index Library by British Record Society. 1968. Page 46.)
NB His ipm was taken 26 Oct 1566.
(Abstracts of Inquisitiones post mortem relating to the city of London, returned into the Court of chancery during the Tudor period, Volume 2; Volume 2. p46.)
(from http://wc.rootsweb.ancestry.com/cgi-bin/igm.cgi?op=GET&db=ances...)
And also -
Robert Taylor, Haberdasher, Alderman Queenhithe, 1592-6, Sheriff 1592-3, (d 31 Dec 1596), had an ONLY dau Rebecca married Sir William Romney.
(from http://wc.rootsweb.ancestry.com/cgi-bin/igm.cgi?op=GET&db=ances...)
Therefore I inclined to believe Mary was in fact the daughter of Anne & Richard Brooke, known by her step father's name, as also was her older sister Elizabeth.
Do we agree?