Keep reading around what you can access on the forum as it will help steer you around before you are age verified.
Personally as a new person I would stick to an M4 platform as you can get parts for them easily and most experienced people know their way around version 2 gearboxes if you encounter a problem.
As for goggles I HIGHLY recommend Revision Desert Locust fan goggles with the prescription insert. I have them and zero fogging and all fields will allow you to play with them no problem and they easily take prescription lens with the adapter (something I am working towards myself). Not cheap at $150 but soooo worth the performance and peace of mind.