As a first-time prop, this is a really good first attempt. It looks proportional and looks like it would fit well.
There are some reasonably easy-to-address fixes on the next attempt, but you should be proud. My first helmet was so big it would have almost been 2 times too large, and my second helmet was so small it cut my ears when I put it on.
The simplest next step is something with just a little more detail, and to take more time cutting and gluing. I know the simple props look really basic and have little in the way of detail, and your skill can get lost in the result.
Looking forward to seeing you around the site!