Can you take a close-up picture of your little one's face? I see some light hairs under the eyes, but it may just be baby fuzz..... Also many foals that gray out don't start showing signs of it right away, and your's looks very young in that photo.
At the moment she looks bay. But, under that bay coat as she gets a bit older, she may be graying out. You will not know for sure for a while. when you go to clip her down, you may see some gray hai5rs mixed in with the bay hairs.
Oh my baby was born the same exact way. His grandmother is a grey dapple appy. His dam is a bay appy and father is a blanketed red roan appy. But he was born the same color as yours, also has slivering down his tail, and when I did a head and neck clip he looked like this underneith. He hasn't been body clipped yet as its still too cold, but I can't wait to see whats fully under there. So far he only has 4 butt spots.
This colt clipped looks like a bay that has the 'mealey' gene to it. The colt in the first posting appears to be bay.... but time will tell. The 'beige' around the nose indicates the possible mealey bay, and if the horse has 'tan hairs' in the top of the tail on either side, that is another indication..