Explanations

WE’RE ROLLING?= (coll.) Are we filming?, Are we shooting? Are we recording?

THE PART= A role in a play, movie, etc.

LOTS OF= (conversational) A lot of.

TUMBLING= To perform acrobatic feats such as somersaults, rolls, or twists.

AND MY BROTHER CASTING DIRECTOR= An incomplete sentence (no verb), which often happens in conversational English. It means: yea, that (all the practice), and the fact that my brother is the casting director.

EVER SINCE= An emphatic form of the preposition “since”.

KID= (coll.) child.

RESPONSE= The public response to an event is people’s reaction to it.

A HELLUVA= A hell of a... = An incredible.

ON TOP OF...= Besides, in addition to, and also.

WHAT UP!= (coll. AmE) This expression usually means “what’s up?” (= hello), but here, it seems to be a kind of expression of agreement (?).

SURE= An emphatic form of “yes” (= of course).

CAN YOU SHARE ANY STORIES WITH US?= Can you tell us any stories?

THE SHOOT= The filming process.

ON SET= At the place of filming.

AFFAIR= A romantic and sexual relationship, sometimes one of brief duration, between two people who are not married to each other.

IT WAS MAGIC= It was fantastic, amazing.

I MOVED= With this sense, this verb is usually transitive, so the usual form would be: “I was moved”. If something moves you, it makes you feel a strong positive emotion.
- That romantic film was so moving it made me cry.
- She was moved by his act of generosity.