The only "disadvantages" to an EXP and a Gold traveling on the same PNR is that for complementary upgrades, when the waitlist goes to airport control each person will be sorted according to their individual status.

But this is easily remedied by either calling AA beforehand or getting an agent at the airport to setup the upgrade request such that the lower status traveler will leverage the higher status traveler's status.

Outside of that it really seems like a personal decision of if you want to use your rewards for Gold status for her and how much benefit she would receive on only 2 trips or so.