Continuity mistake: The grown up Billy in the end of the movie has brown eyes where as Jamie Bell's (Billy's) eyes are blue.
Continuity mistake: When Billy Elliot is looking for Mrs Wilkinson's house he is wearing his school bag over his shoulder. When, later, he gets out of the car he no longer has it with him.
Continuity mistake: When Jackie is inside the bus leading to the mine, an egg hits his window, but when the bus is viewed from outside, the window is clean.
Continuity mistake: When Billy punches the other boy in the Ballet School after his audition, he hits the boy's face on the left side, but the boy grips his right side after falling down.
Continuity mistake: When Mrs. Wilkinson goes to Billy's place to talk to his dad, he goes on a frenzy in the loo. The toilet paper on the floor changes positions between the wide and close-up shots.
Continuity mistake: When Billy goes to the gym and shows Mrs. Wilkinson his mom's letter, she raises her right arm holding a cigarette. From the opposite angle it's lowered.
Continuity mistake: During the pillow fight, the amount of feathers on Billy and the girl are not continuous between shots, especially when Billy's back is covered in feathers and he bends forwards towards her.
Answer: Some time has passed since Billy left home and became a professional dancer. Jackie is older now and not as physically active as he once was. He has also seldom left his small, provincial town, and being in a major city like London is a little daunting for him, so he is a little uncomfortable and out-of-place.
raywest ★
I'd agree with "overwhelmed" (or in awe), but not to the point of being "daunting" because he was eager and excited to see what Billy had become and was not trying to avoid going there. (It was more like he was trying to not let on how excited he actually was).
KeyZOid
There's nothing to suggest that he was excited or eager, let alone that he was trying to hide it. It's more likely he was simply overwhelmed.