Becky Thill gives a marriage date of Dec. 20, 1690 for William and Martha. That would make William 19, but Martha only 16 based on Martha being born in 1664, as Becky says. Bill Robey gives a birth date for Martha of 1680, which would make her only 10 years old at marriage.

For many more sources, see Becky Thill’s web page on Sidney Wynne: http://wc.rootsweb.ancestry.com/cgi-bin/igm.cgi?op=GET&db=ttg13&id=I2597

These establish her parentage, her marriage to William Chew, and that their daughter Sidney married Charles Pierpoint.