Greetings from the US! I believe your birth date for Mathilda Killinger is probably correct, because the christening date would of course be after her birth.
Mathilda Killinger Hoener's date of death is 23 Feb 1885. She died approximately 3 weeks after the birth of her last child, Katie Grace Hoerner.
John Andrew Hoerner, b 22 Dec 1836, c 27 Mar 1837 at Zion Lutheran Church, Hummelstown, Dauphin County, Pennsylvania, US, died 26 Aug 1908.
John and Mathilda were married 6 Mar 1862 at First Evangelical Lutheran Church, Harrisburg, Dauphin County, Pennsylvania.
John and Mathilda are both buried in the Union Deposit Cemetery, Dauphin County, Pennsylvania.
You will recall that Mathilda had a child prior to her marriage to John Hoerner. That child's name was Clara Steeley.
John and Mathilda then had 10 children:
Lavina, b 5 Dec 1862 John W., b 18 Jul 1864 David, b 29 Jul 1866 Milton, b 23 Apr 1868 Alfred, b 7 Mar 1870 Emma, b 5 Mar 1872 Franklin H., b 7 Aug 1873 Barbara Anne (Annie B.), b 29 May 1876 Edwin M., b 26 Jul 1881 Katie Grace (Grace K.) b 31 Jan 1885
Katie Grace (Grace K.) was my grandmother. Everyone knew her as "Grace" rather than "Katie." As a very young child I remember going to visit 3 of her siblings, my great-aunt Annie and my great-uncle Ed and great-uncle Alf.
Now, going back to Grace's mother, Mathilda, she is listed as 1 of 4 children on the 1860 US federal census, Harrisburg, Dauphin County, Pennsylvania: The children of Michael Killinger and Catharine Lehman Killinger are listed as follows:
Cyrus, b abt 1838 Matilda, b abt 1841 William, b abt 1847 Lavina, b abt 1851
I was not aware of Louisa, Margaret, and John, who would have been older than the children listed on the census. Is it possible that they were living with other family members at the time of the census?
Also I have no information about Rebecca, Lydia, and David.
I have more information about the families Hoerner, Seibert, Killinger, Lehman, Oberle, Brandt, and Windnagle.
I can also give you information about the descendants of Grace Hoerner Geiman.
Thank you for the additional information you have supplied to me, and please let me know if I have information of interest to you.