With the AAXP bonuses it ain't that hard to grind AAs. I mean in an ideal world I would start on AAXP BEFORE 85 but it isn't the end of the world to be 85/0AA. You just have to pick your spots, maybe fight only LBs if you're a tank, until your defensive AAs build up. Remember just doing the daily instances for your level will pile on AAs at a ridiculously fast pace. I did the two level 90 and one level 85 missions every day for a month for some 95 alts that started with ZERO AA's (I had PL'd them up using the Infilitrating the Guardian anniversary mission, back before they nerfed it) and I got them all to over 3000 AAs in that month. Was taking me less than an hour each morning.
The daily tasks give decent AAXP even for those missions well below your level. Good place to start until you get up to a few hundred AAs.
Good luck!