When you start to learn your first instrument it feels unconquerable. You don’t understand the theory, your fingers don’t work along, and your rhythm is atrocious. Your just not a musical person.
The first instrument is the hardest. Your collective knowledge is zero. By the time you are competent you understand music and notes, you can hold a rhythm and you can move some of your fingers independently.
Every instrument hereafter gets easier. You transfer these core skills that you did not possess with the first one.
This is true for all new skills. Your first job, or first business, or change in an industry can all benefit from your existing arrows in your skills quiver. All you need to do is identify which skills are transferable, and put them to use.
Over time your collection will be so unique that you end up the only person able to solve a specific problem. This is the story of Benjamin Fraklin and Abraham Lincoln.
No-one starts at zero. Use what you have.