IMHO, she should be absolutely fine. No need to rush just be brisk and keep moving.

UNLESS, incoming is late, in that case she may have a problem, but with a single PNR she will just be accommodated on the next flight (which will be the AA flight 1:15 later (and from T3) or the BA flight 2 hrs later). On the one occasion I missed a connection, I was rebooked seamlessly and met off the first plane and handed my new boarding card