A username ending in a year often indicates when that user was born but, from the wording of your post, I'll assume that doesn't apply to you, and that you're still at school.
With few very limited exceptions (such as child actors), it's illegal for anyone to employ a young person under the age of 13. Schoolchildren who are 13 or 14 years old can't be employed for more than 5 hours on a Saturday or 2 hours on a Sunday. Those who are 15 (or 16 but before their school-leaving date) can be employed for up to 8 hours on a Saturday but still only 2 hours on a Sunday. Further, in most areas, no school child can be employed unless their local education authority has issued a permit. (A school can block such a permit being issued, or have it withdrawn, if the employment appears to be interfering with the young person's education). See here:
https://www.gov.uk/child-employment/restrictions-on-child-employment
Jobs for young people are incredibly hard to find and (with the exception of newspaper rounds) hardly ever advertised. The only way that you're likely to find a job is by calling on a lot of employers (either in person or on the phone) to ask if they've got any work going. There's absolutely no point in trying big national companies (like the major supermarkets) but some independent corner shops sometimes offer work to young people, as do market traders. Hairdressers will sometimes offer 'sweeping up' work to young people as well.
However it's worth remembering that self-employment isn't covered by the rules I've referred to above. You're free to run your own business (perhaps offering ironing, car-washing or dog-walking services) without restriction.
Good luck!