Currently you can order search results by edit date or creation date, with newest on top. It should also be possible to order them with oldest on top.
Description
Description
Related Objects
Related Objects
Event Timeline
Comment Actions
T197525: Let users sort results by time (older or newer results) implies that this is already possible.
If it is not: Please follow https://www.mediawiki.org/wiki/How_to_report_a_bug and provide clear steps to reproduce, expected outcome, actual outcome.