That's horribly early isn't it? (((Hugs))), you must be tired. I just wonder - what are you actually doing with her at that hour? I see you've said you have eat, activity then sleep after 1h45 - are you actually getting up and starting the day? I would suggest that you treat that hour as a night waking - lights off, no interaction, feed if needed then straight back down and no lights on or getting up until a reasonable/acceptable hour of the day, say 6am (very reasonable with a 6pm BT). The trouble with actually starting the day so early is that her body clock will start becoming accustomed to being up at that hour (all sorts of effects from light/stimulation on natural body clock rhythms) and you want to send a clear message that it is still night. The other issue is that it means her first 'nap' is very early and actually an extension of her night time sleep - and therefore reinforces the early start. In an ideal world you want to delay the first nap until a full A time after 'acceptable' WU - so treating 6am as WU you want to try not to allow a nap until 7.45am.
You may also want to give some consideration to bedtime. It's tough when they are up early but an early bedtime can very easily lead to an early wake up in the morning. 12h is an ideal night but 11h is totally acceptable - which realistically means 5am is a fair and reasonable time for her to wake for the day if bedtime is 6pm. We got in a horrible early wake up cycle with DS when he was younger and actually it was one of the times where accepting an 11h night as the standard, and pushing bedtime later really helped.