I found this listing in the 2006 edition of The King's Passengers to Maryland and Virginia By Peter Wilson Coldham. (If I give the link to the previews at the books.google site, Ancestry.com will probably delete this post. You can search for it, or ask me.) I also found what appears to be her mentioned in Proceedings of the Old Bailey, London. I'm not sure if she used the name Frith in MD, but she was tried under the name Firth. The sentence was probably transportation for 7 years, but of course we never know if the defendant returned to England.

To see ALL 192 of the Friths mentioned in the Proceedings of the Old Bailey, see
http://www.oldbaileyonline.org/search.jsp?foo=bar&form=s...

p. 9
Felons transported from London by the Gilbert, Capt. Darby Lux, in October 1720 and registered in Annapolis in May 1721. (PRO: T53/28/331; CLRO: Mss 57.7.8)
Middlesex: Frith [Firth], Elizabeth, aged 19, fair

http://www.oldbaileyonline.org/browse.jsp?id=t17201012-25-de...
Elizabeth Firth, Theft > grand larceny, 12th October 1720.
Reference Number: t17201012-25
Offence: Theft > grand larceny
Verdict: Guilty
Punishment: Transportation
Elizabeth Firth , of St. Martins in the Fields , was indicted for feloniously stealing a Poplin Gown and Petticoat value 8 s. a Camblet Gown and Petticoat value 6 s. A pair of Stayes 2 s. a Silk Hood 1 s. and 5 s. in Money, the Goods and Money of George Leadbeater, on the 12th of September last. It appeared that the Prisoner was the Prosecutor's Lodger , took the Goods and went away with them; that she was taken 4 Days afterwards, and the Goods found upon her, which were produced in Court, and owned by the Prosecutor. The Jury found her Guilty. Transportation.