What kind of mistakes can a new meditator in his/her early 20's avoid? I am currently in my late twenties and I began meditation in my early twenties. I often think that the path that I am on being correct as it is and it has provided it's justification through practice- I am unsure what I will think of me in my thirties or forties I am pretty certain I am making some mistakes that I am not aware now and will be with the passage of time. 
This question stems from the fact that I personally know how my meditation journey began as a yuppie and how I thought more an did less. Also following books and authors without knowing that it's not really my own wisdom but someone else's. Trying to be someone else unconsciously without thinking what I want from my life. Intellectual discussions and tryin to prove a point without having metta for the other person. Learning to accept family as they are without doubting or questioning their motives (still beats me). The list goes on. 
Well I am sure there are many more experienced and mature meditators who can probably provide a glimpse on their twenties. All this only for a healthy comparison as I don't have any friends my age who take meditation seriously. 
Metta
Choose the middle between all extreme contrasts.

If you are going too fast, go slower.

In your meditation you might choose a kind of meditation.
Then you would try to keep yourself on doing only that one thing you have choosen.
You would be disturbed by thoughts or feelings and might not keep yourself on one point.
This is OK. This is meditation: if you come back from things which disturb you, back to point you have choosen. - Many people might think they do not meditate if they can not keep themself on one point - that is wrong.

I think you allready know you need patience, but also there might be a time where a change can help.