Can I email a school re: asshole teens?

EDIT: I emailed the school. The mocking the language was the straw that broke the camels back. Such bullshit, and totally unacceptable.

Feel like an old fart here, but I live very close to a Daybreak shop and 5 minutes beyond that is a secondary school.

Every day at half 3 there's like 20 teenage boys outside gathered at the door. Popped in today and noticed a security guard outside. He told them to wait, but they started playfully pushing to get inside. The SG was getting quite irritated, as the young girl behind the counter was making 99s, and the lads were whistling in at her while she worked.

A little teenager behind me in the queue inside joked can he go next and I said no, so the lads started pointing and laughing at me. I had my headphones in so didn't hear/don't really mind that much.

As I paid and left, I had to push them out of the way to leave the shop, as the security guard tried again to wave them off.

I noticed a woman there with her little one on a scooter standing there confused by it all, and I said just go in passed them. I asked the group to get out of the way, and one of them snapped "we're in a fucking queue". I told him to fuck off out of the way for the woman and her baby, and they moved. When I passed them again, there was a mother and teen daughter speaking an eastern European language. One of the boys from earlier started this mock language thing, and pretended to sneak up behind them. I told them to fuck off again, and that they were intimidating people.

Home now, but I feel like I should email the school or something? It's a 3 minute walk between the school and the shop, and these are middle class kids being absolutely horrible on a daily basis. The poor security guard can't lift a finger to them, so they poke him, get way too close to him and stand around roaring laughing.

I doubt anything would come of it, and no one has been hurt or anything, but it's totally unacceptable. I came so close to slapping the lad mocking the mother and daughters accents, and I feel like the school should be aware of what they're doing on their break/straight after school.

Am I a fool for thinking this, or do I just need to calm down and move on?