I'm a 26 year old female and suffer quite badly with anxiety.
Constant chatter yet nervous to read in front of a class - I'm the same, I am absolutely not anxious around friends or even some people I barely speak to in my college class that I'm just used to being around, in fact to my friends I'm sure I come across as quite confident, ask me to do a presentation or read in front of the class - forget it - just the thought of it makes me panic.
Lack of concentration - if I am feeling anxious, it is impossible for me to concentrate with all the other anxious thoughts and scenarios and worries going on in my brain.
Nervous laughter - I have never noticed this personally.
Leg bouncing or messing with pen - I do the leg bouncing, jiggling, shaking. Can't tell you why but I do it. I think it is a bit of a distraction or comfort perhaps.
Scared about new situations - yes but I almost think that's normal, isn't everyone?
Doesn't like doing things on her own (has to be with friends) - I experience this in the aspect of, for instance, starting a new gym class, I absolutely couldn't do this on my own, i would need to have a friend with me for comfort. But I can manage to go to the supermarket myself etc.
Cannot make decisions - I have never noticed this personally.
Binges food - yes, daily.
Worried about bad grades - yes I worry about not passing assessments and not progressing to uni. But once again, I feel this is a very normal worry that someone not suffering anxiety might also have.
Forgetfulness - when my anxiety is particularly bad, I can become forgetful, I think this comes under the same reason as not being able to concentrate. There's so many thoughts, scenarios and worries in your head, it's hard to keep everything straight in there.
Procrastination - I have always been a procrastinator, before I suffered anxiety. And I know plenty people without anxiety that procrastinate too so could be unrelated.
Hope this helps some.