New project or new level for creating another scene?

Hello, I’m new in this community and also new to UE4.

I’m still learning the basics of the engine but I have a question on creating a new scene. So far I’ve created a new project, made a new level and imported my own assets, now the project has lots of 3d assets and textures and I don’t know if I should create a new project or just a new level. I don’t know if it will affect performance on creating a new one and keep adding more levels in the future. These levels are just for practice to get to know more about UE4. So, new project or new level? Also, I’m not going to use the recent 3d assets and textures coz I’m going to create new ones.