linbren,
I don't have any specific information, but do have a marriage registration index record that just may pertain to Mary Ann, as follows:
General Registration Office, Marriage Index, Belfast District, 1871, Vol 6, p. 361.
You should pursue getting a copy of the actual marriage record, which should identify Mary Ann's father and his occupation, where they were living at that time, and also may possibly show both Mary Ann's specific age and any siblings who may have been witnesses.
If you do find out more, I'd be interested.
Jim Culbert
Guild of One-Name Studies:
Culbert Registration No. 4096
http://www.one-name.org/profiles/culbert.html