I have a tendency to write way too much, so I'll try to make this as short as possible. (i said try!) o3o;; Also, don't take any offense to whatever I might say - it's all for your improvement, which I can see a lot of in your recent drawings. So bear with me!
Her pose is very cute - matches well with the theme. I just wish there was more expression in her eyes - maybe if she had eyebrows it'd look better? Her neck is also a little too twisted back; if you really wanted her head to be that far back, her whole body should tilt back as well.
Her lower half looks good - I'm just wondering where her knees are.
I like how her bangs are quite spiky, but the main problem here is the ponytails. Her hair needs to flow a little bit more to look natural.
Let's start with ponytail A - the flow is fine, but the big crack on the left makes it look awkward, like her stylist was having a little too much fun with the hair gel and decided to shoot pens through it. It was a good experiment, but you should try to make the gaps smaller or try making gaps with thinner strands of hair. does that make any sense? o3o;;
Ponytail B - it looks as if her hair was naturally wavy and one side of the ponytail was straightened and the other was left natural. Try to be a little more consistent with your drawings! >3<
I have no problems with the colouring, well done! The blush in her cheek on her left is slightly lower than the one on her right, though. o3o I really like how you coloured her eyes, too. The highlights give a really glassy effect which makes it very aesthetically appealing!
The concept is really cute! I do like the very simple and girly background you've chosen. Overall, it's a very cute and pleasant drawing - it may not be detailed, but it's very nice.