do you know anything that is for younger students(year12) for work experience to put on a personal statement?
Unfortunately, not much you can do as a year 12 student to get genuine work experience. Its pretty hard to get a placement at a decent company as a software engineer, the competition is fierce and only very best the get the chance after multiple stage interviews. I worked as an embedded software engineer for my placement but I got this between 3rd and 4th year of my university degree.
In your case, you can work on projects, upload them to your GitHub profile and simultaneously you should be grinding hard on leetcode make sure you are sharpened. You can try fork/contribute to open source projects. Have a look at this Clement guy, he worked as a software engineer for Google. Granted, this guy is quite special I don't expect you to have projects like that on your GitHub/portfolio but you can use this as a target.