Youth dribbler and defender running parallel

[KansasJoe]

New to officiating but coached two boys from K - 7th until the school takes over. Decided to officiate on the weekends with my 15 year old. Doing the lower elementary grades which I enjoy because I get to do quite a bit of coaching while officiating and everyone seems to really enjoy that. Done 31 games so far and will end up doing about 50 by the time the season is over.

Here's a situation which comes up multiple times. B1 is the defender in legal guarding position and A1 is ball handler. A1 drives but instead of B1 sliding over to keep his torso between him and the basket he simply turns and starts sprinting alongside A1. If I see an extended armbar I'll give them a warning and then call a foul since they're restricting A1s movement. What if they're side by side so shoulder to shoulder and A1 jumps sideways into B1? If B1's torso takes the contact then charge but in this case it's their shoulder. Not in legal guarding position but B1 has a right to a place on the floor.

Another scenario is if A1 goes up for a shot and B1 jumps with him there's minimal contact but they both go flying forward. Both scenarios are if they're perfectly even because if A1s head and shoulder is past then I'd call a defensive foul if there's contact.

Probably an easy question for you experienced refs but want to make sure I'm giving my best and having accurate calls which they'll see as they get older.

Thanks,