4yo is in his own bubble!

My son is just turned 4 and always seems like he’s in a world of his own! He is where he should be developmentally but I can shout his name 5/6 times before he answers sometimes it gets really frustrating, he’s not ignoring me either he’s just zoned out.

He wanted to start a soccer class, he literally doesn’t listen to anything they ask them to do. The kids are all the same age.

Should I be concerned? He’s fine playing with his brother and sister at home but just doesn’t listen!

Any advice for helping him not be spaced out around bigger groups of kids? He’s pretty quiet.