I think I was trying to make it like it was windy, and intended to add something in the background to show this, but never got around to it.

if she is walking why the yellow scarf is flowing that much?

 Thanks! That's exactly the kind of help I need.

Also, your avatar is very cute. :)

Nice first try :) She's got a lot of character.

At that speed, I highly doubt her scarf would be flowing so far behind her unless it's really windy or something.

She looks like she's just moving her legs back and forth in space; she never lifts her legs and propells herself forward on the ground. The animation's also jerks when her legs are most spread apart.

Try walking yourself or asking someone to walk in front of you to get the feel of it. Also, this might help.