Marytheres...
Making lasting judgements on a child's behavior (whether positives or negatives or anywhere else) in the first MONTH (let alone week?) of a new environment is ridiculous.
Different people (kids and adults) will react differently to change. My dh is very introverted and will always be the one to "sit back and watch" in a new environment. I am the big-mouth who can't shut up (trying to get better at this). Once dh is comfortable, he is funny, quirky, social self.
Social reciprocity struggles should not be interchanged with introvertedness or shyness. These are different symptoms that may appear the same on the surface to a novice, but arise from different roots underneath.