There really isn't anyway to tell what shade of palomino she'll be based on her foal coat. She may shed and be really pale or shed and be dark. She may also change shade with age or even throughout the year.
^^Agreed, there are so many changes that a foal goes through in those first few months/couple years. She may end up going sooty and be really dark or she could end up going really uber light, there's just not way to know.
You likely won't have any idea what shade she'll be until she's shed out her 2 year old year.