I wouldn't consider a 21 year old a kid nor would I consider one old. Its a matter of opinion oh wise one who understands all
Doesn't have anything to do with a number. More with the maturity level. Plenty of 21 y/o act like kids. Spoiled kids at that who think everything should be handed to them. Act like a kid and you get called a kid IMO. Not directed at you BTW.
And to you guys that are defending texting and phone use during class this is a perfect example of not pay attention. I could give two chits less if you texted or played with your phone all through high school and still graduated with honors. That just fits with the "all about me" self-centered attitude so many kids have these days. Just because it doesn't or didn't distract you doesn't mean it isn't distracting someone else. They may be too worried about checking out your phone or what yoou are doing with it to pay attention to what is going on. I have a son who is ADD and he has a hard enough time focusing without games, texts and calls disrupting the class.
Sorry but there is nothing that important that it can't wait until a break, lunch or after school. If mom or dad needs to get hold of you in an emergency situation I am sure they know how to call the school.