Am I overthinking?

So me 16M and my friend 17F were playing volleyball with another friend of her in our local playground, It is a quit big ground so people come for walk, kids play, do cycling and all those things.

So we were playing at the corner of the ground and suddenly one kid(around 11-12yrs old) came on his cycle and said"Hi cutie" To my friend and she is very funny girl so she replied "bye cutie" And i asked her if she knows him and she said NO

I was shocked and confused like how can a kid just pass compliment on a random girl who is 4-5 yes older than him like I can't even talk to my crush who is my batchmate

Like I was thinking this kids will grow up and could become menace to society

So my question is Is this behavior normal? Am I overthinking?