Skittish when feeding

Question
We recently got a puppy (Basenji/Harrier mix) from a local shelter. She is doing very well and is becoming settled into our home.  I am somewhat confused at her behavior when she is fed.  Whenever we prepare her food she starts to get really excited. Her tail wags, she starts to run around, she is obviously in a good mood.  The second you bend down to put the bowl on the floor she gets skittish/nervous/scared and runs a few feet away. The second the food is on the ground and you step away, she is at her bowl eating. If I prepare her food and bend down when I approach the spot we place her bowl, she will approach, but does so warily. Whenever we come inside from a bathroom trip we try giving her a treat but she will not come near us unless we are down on her level or standing there calling her name for two minutes.  We first thought that she was scared if you approached her directly while standing, but she actually gets excited when someone approaches her, dog or human. We don't have any other pets or children so I don't know if she is afraid someone else is going to go after the food.  Do you have any ideas or suggestions?

Answer
Kimberly;
I am really respectful of those who choose a dog to "Rescue"...but, that word implies one thing..the dog has been "Mistreated"! So, do be aware, that you are in a transition, and yes, she does not "TRUST" anyone or anything in her environment!!!
So, do what you are doing, and do take time with her to make any moves...Consistency is going to be the "Key" to her successful calming trend.
It may take her 6 months or more to acclimate to you. So, do be patient. Give her the food, call her name, and when she approaches, don't go over right away, just "Praise" her and tell her she is a good girl...this will give her the confidence.
She clearly wants to "Give you her Heart"...with the tail wagging, and mannerisms..so, again, she has to be the one to accept you, and her new surroundings!
Time and what you do to make her feel good about her are her issues.
And, I feel that you are a sensitive caring person, and will do just that!
Let me hear from you if you need further help,
And please drop me a line later to tell me how she is doing...
I would appreciate your feedback at the Website with a rating to my answer, this is the last day of the month, so, all counts!
Thanks again, for choosing me to help, and I hope I have!
Best regards,
Melissa