The contents of DefaultTiddlers uses filter syntax, which allows for more than one filter operator to be applied.
To get the results you want, add a sort[] operator to your filter expression, like this:
[[tag[HelloThere]!sort[created]]
The parameter of the sort operator (i.e., created) indicates the field to sort by (the default is the title field).
Preceding the sort operator by "!" uses *descending* order (the default is ascending order).
enjoy,
-e