Salem, Mass., church records mention the baptisms of three daughters of John Black: Lydia, Dec. 25, 1636, another Lydia, June 3, 1638, and a daughter not named in the record, Nov. 27, 1640.
From the probate records [see here, obviously assuming in birth order] it appears that Lydia, baptized June 3, 1638, was the youngest daughter living in 1675. Persis Black, who married Robert Follett, Nov. 29, 1655, was younger than Elizabeth. Presumably, Elizabeth was born about 1632 and Persis about 1634.