Margaret might have been a year or two younger and been the first child born in Missouri. The 1830 census indicates she was not yet over age 10.
I have never found them after the marriage record. Perhaps Margaret died before 1850. There was a William G. Oldham in Hannibal, Marion Co in 1850 - he was a brickmaker, born in KY, age 20 and had a wife Rebecca E. age 25, b. Ohio, and two sons, Wm. W. 8 and Thomas R. 2, both b. Ohio.
Margaret FRY and William W. OLDHAM were married on 19 July 1838 in Marion County, Missouri.140 William W. OLDHAM was born about 1818.
At marriage: "he being underage but no objection"
William Oldham served in the Seminole War under Capt Curd, along with his future brother-in-law, John Fry.