She probably is quite a mix of at least 2 breeds, especially since she was at a shelter. Many shelter bunnies are dropped from folks who got them at pet stores and didn’t want them, or were babies of the same. Pet stores never buy pure breeds – the get cheap mutts. (Usually the cutest anyway!)
The dark ears/light body remind me of my bunny that is an English Spot mix. Sable is her color as MB said, and she is very, very beautiful!
The best time and way to tell is to wait 6 months to a year and then study breeds. By then she will have reached her full size and weight, and her adult fur texture will tell you also, along with the ear positions. Certain breeds grow to certain sizes, (dwarfs vs. minis vs. medium to larger breeds), the fur is only velvety on babies unless you have a rex. The head shape is a good clue, and the ears, if they flop down, makes her a lop. Not likely from the look of them, btw.