Plagiarism

Alr so i have my a level computer science coursework due in and ive done all of the analysis, design, testing and evaluation - the problem is my development. You see my coding isnt to that high level so i was going to use a bunch of yt videos to help me code but i found this one video that had everything i needed from the entire code (which is almost exactly what my coursework is) to the graphics and i used this in my coursework, i did follow the video and coded and tested it all myself but at the end if the day its the youtubers code and so ehat ive done is ive chnaged some of the graphics slightly (colour wise and the characters are my own) and a bit of the code but i was going to add a lot more and chnage a lot more but i didnt have the time. I was wondering if id get marked down for plagiarism or smth and if i would fail the entire coursework for this

Alr so i have my a level computer science coursework due in and ive done all of the analysis, design, testing and evaluation - the problem is my development. You see my coding isnt to that high level so i was going to use a bunch of yt videos to help me code but i found this one video that had everything i needed from the entire code (which is almost exactly what my coursework is) to the graphics and i used this in my coursework, i did follow the video and coded and tested it all myself but at the end if the day its the youtubers code and so ehat ive done is ive chnaged some of the graphics slightly (colour wise and the characters are my own) and a bit of the code but i was going to add a lot more and chnage a lot more but i didnt have the time. I was wondering if id get marked down for plagiarism or smth and if i would fail the entire coursework for this