Hello! Great project you've got! To answer your questions:

Casting Epoxy Resin: Casting can be cost-effective and give you a decent finish but might not match the precision of machining without some extra work. It all depends on the mold quality and how you handle the curing process.
Machining Glass Fiber Reinforced Epoxy: Yes, you can machine this material, but it's tough on tools due to its abrasive nature. Specialized tools and careful planning will help a lot here.
For a project like yours, exploring other materials could be a good move. Maybe look into some advanced material options that could offer the precision and durability you need like here: https://www.kkrstone.com/

Hope this helps, and good luck with your graduation project!