Don't be put off by other people getting work experience at a young age. I started looking for work experience at 14 and wasn't able to get anything until half way through Year 11. I spent the whole of my AS year working during all weekends and holidays full-time except for Christmas, and managed to get over 15 weeks during this time. I now hold offers for two universities so far this year, so you do not need to worry about not having long amounts of work experience. Whilst this does show that you are committed, the quality of your work experience will be much more important to show how much you have actually learnt. It would be better to have a week on a dairy farm and appreciate/understand that field a lot more than spending 6 months working on a farm and did not ask questions or get involved with it!