I'm not sure but i'd say you have a girl - males usually have a very prominent scent gland on their stomach(in the middle) and their vents (openings) are further apart than girls, the picture makes it seem like her bottom is longer/not rounded but that may not be the case
i hope this helps, perhaps you could hold her and gently check her vents and/or look for nipples - which are hard.to find but not impossible
I found a diagram to help you - it helped me when i mis-sexed my own dwarf
I hope this helps