Junior fears

You shouldn’t be 🤗 . My advise would be respect what your team built but you can always go back to the previous design with the History.
Also one good practice is to have an exploration file where you can mess as much as you want and then you can move the final design to your teammate file

Thank you. So much i will definitely do that as practice

You can duplicate and learn by community like a https://figma.com/community, Figma has a lot of tutorials in YouTube. You can growth with other people

One thing that i have internal conflict with is that i asked myself if that will make a good designer if i copy something that i like instead of starting from the bottom

If you already know the basics of how to use this tool, you can try creating a design, which I emphasize why I recommend the community is, you will understand more neat design structures or organize designs more effectively.
For example, you make a button repeatedly every time you want to add a button, if you learn from other people’s designs you see their designs actually use reusable components over and over again from 1 design.