Hi there,
I started BW with my DS at 4.5 months but I think there are a couple of things I can suggest.
In order to get her used to her room/cot have her lay in her cot while you put away clothes/tidy up etc. You will indicate to her that this is playtime by singing/chatting to her while she is there and obviously the lights are on. Put a soft toy or book in there for her to play with. Maybe you could get a mobile that easily detaches for sleep time if you'd prefer that.
As for A time, many babies that age do best with under 1.5 hours of A time, but if your lo is thriving on a 3.5-4 hour easy, is gaining well and sleeping well we go with the old saying "if it ain't broke, don't fix it!"
As for sleeping from 11pm-7am-I send out a great big YAHOO! There is absolutely nothing wrong with that. Your little one is obviously taking in enough calories through the day to carry her through the night and that is our goal!
I know this must be confusing for you, to be getting so much conflicting advice. Ask yourself-did she seem happy/content on the other routine? If so, I'd say stick with it.
HTH