She was "soixante dix neuf" (69) years old according to her death record in 1830. But there's no Mackwiller records before 1792 on Bas-Rhin.fr, so can't investigate there.
Found on Bas-Rhin.fr. This event actually has two records in the Steinseltz Heiratsregister – probably because it was the first one of the new year, and also the first one with a new recorder (different hand-writing).