YANBU.
Most of my generation had part time jobs in local/independent businesses like corner shops, Bed & breakfasts, cafes/restaurants, milk men, leaflet deliveries, paper deliveries etc. Hundreds of thousands of such businesses have closed in the last few decades.
The likes of big supermarkets, Amazon, Travelodge, chain restaurants etc don't take on young school kids.
Partly because of the new laws that were introduced to "protect" youngsters in the workplace, i.e. not allowed to work in kitchens under a certain age, not allowed to work early mornings at a certain age, some councils requiring employers to get approval for each person from the local authority before hiring them, etc.
But also because they prefer adults on zero hours contracts.
Sadly this is what happens when "big business" takes over aided and abetted by politicians who are out of touch with reality. Proposed minimum wage hike for youngsters is the final kick in teeth.