Girl's 12-17 do you ever feel weird when you catch a kid in your class looking at whatever boobs you have?

It depends. If a guy is full on staring at them, then I would be freaked out. I mean, if I catch someone looking at them, I feel flattered like the other girl said. I'm sorta thinking: awesome, I have boobs that are worthy of being looked at.

It makes me uncomfortable no matter whether you just glance or full on stare. Most girls are insecure at that age so the ones who think that they are good looking will be flattered while insecure girls will be uncomfortable.

I feel flattered. And then I break the stare by turning away or obstructing their view with my arms.

you should add your definition of 'looking at'. i think gazing at them the whole time, looking directly at them for a second or two or looking very quickly from the corner of your eyes makes a difference in how the girls feel.