Oh yes the judge will see her sudden wanting to be involved as what it is.... Most often whit a situation as you are describing there are not too many porblems getting things resolved... Also keep in mind that because this is not some kind of 'criminal' case she will have to pay her own attorney....sometime the other parents just gives up when they realize what they are going to have to do....
I presonally don't think you have a real big problem... Nothing that a few dollars and some frustrating court visits won't change--and I completely agree you do need to have protection in the even anythiing terrible were to actually happen.... (Big Prayer Not) and also I personally feel a child deserves to have a RELATIONSHIP with the parents...married or divorced...the little girl deserves a mother of her own...If her bilogical mother isn't willing to be that then I am so happy the little girl has a mom like you...............
I can imagine there may be bumps in the road--but, this is happening all the time now so a good attorney should have no problem walking you through everything....
Good Luck,
Anna