It's very difficult to tell. I've done a bit research on this recently and have read that the violet on the neck area doesn't indicate for sure a sf violet sky blue but if your budgie's tail feathers and wing feathers are turquoise rather than navy, it is likely to be a sf violet sky blue rather than cobalt.
Violet is very hard to detect in photos. It usually doesn't show in pictures that are not taken in natural light.
From the picture you posted, she looks like a normal cobalt. She is very cute!
Can you get a picture of her in natural lightning perhaps?
Most blue series birds do have a violet hue where their head color meshes with the body color. Like everyone has said it is very hard to tell a violet just from a photo. But from what I can see your bird isn't a violet.