Wow! That is actually so good for your first time. 
Highlights
I’d say apply the highlight to her chin, neck, the bottom of her nose, the bottom of her bottom and top lips, the bottom of her brows, the bottom of the fringe + the bottom of the front section of the rest of the hair and you could even lightly apply it to her eyes. If you wanted to go a step further, you could apply it the underside of her top lashes.
Shadows
For shadows: right under the chin/jaw, the side of her neck that’s side beside her hair, the side of her face that’s right beside her hair, you could also add a soft shadow of her nose (to the left side of her nose), the furthered sides of her hair + the top of her hair that isn’t being exposed to the light.
Those are just what I’d do. Obviously you can deviate, it’s your edit, hence it’s totally up to you. But fr, you’ve done a really good job. I mean it.