Thank you Ladies.  She's already had her first molt and is fully feathered. The other female ducks are great with her, they have each been in her pen for days at a time with her and no troubles. My Drake has topped her three times while I've had her in for visits  with the big ones.  Twice she allowed him with no protest, once she kind of yelled at him for it LOL  I hatched her from one of my big girls' eggs, she's been watching the big girls and now does the head bopping come get me dance when the drake comes near her fence (I have the duck pen partitioned with a wall of doubled chicken wire).  
I guess it's time for me to accept she's a big girl and let her be with them.  I think I'll give her a few hours over the next fews first then let her move right in with them.  I was worried about her being too young to be topped by the drake. 
Michelle