She starts at Level 1. You either choose to go along with Inquisitor Levels and just have a duplicate or you can Multi-class her since level 2. As Desi said she is still a pretty strong character in general as a full Inquisitor, but if you are not looking to replay the game
and want to bring her
AND don't want to overlap with your MC then just do it at Level 2. She has decent WIS, STR. If you are going to multi for Martial you can probably postpone it until Level 5 to get Bane? Not sure if its worth it. Your Divine Favor will also be +2 at Level 4 which for important fight will negate the 3/4 BAB when you go for 5 Level in Inquisitor.
Considering she has 16 WIS and the basegame doesn't have Druid companion and she has Neutral alignment, you can probably go for Druid just for novelty. Missing one level sucks a lot as a Druid though but it's not unplayable. Your Animal Companion will be 1 level lower unless you burn a Feat for it. Or alternatively you can go for Domain although I am pretty sure taking animal companion is still better