I can't decide my course

First thing to do would be to check if you’d meet the entry criteria for music
If so then look at the course pages for a range of unis to get an idea of the course. If not youll need to think about whether you are willing to put in the effort and possibility delay starting uni to meet the requirements.
Realistically, if you did want to change courses then you’d only need to do some wider reading, an online course and maybe sign up for a residential or something to give evidence for your interests.
Also im not sure but i think that a lot of music type degrees are offered by conservatoires which you can apply to directly instead of through ucas so you could potentially apply to both 5 unis for chem and some for music… please check whether ive got this right for unis youre considering though before you submit your ucas form cos im not an expert and it might vary!

I am applying in January for university but I keep having second thoughts on my course. I'm applying for chemistry and have done all of the supercurriculars, written my statement for it etc, but I keep thinking about music. I haven't done any supercurriculars related to music apart from playing in ensembles and know almost nothing about the degree, but I keep having doubts if I'm making the right choice as music is such a big part of my life. I know I've rambled but I have no clue what to do and any help would be appreciated !!