Oh! I think you will love it!
You can take classes both ways, 100% on-campus or a blend of online and on-campus.
I do the blend as I have a day job, but if I did not, it would be super fun to be on-campus. They offer student housing too! I'd be like a college student again.
The intro classes you can do online, which I have been doing. The middle classes are a mix of offline with on-campus lab work. The advanced classes are on-campus as the exams require lab work.
There are two campuses in the US. The main campus is in Carlsbad, CA (north of San Diego); the other campus is in NYC. Even though I live on the East Coast, I went to the Carlsbad campus to check it out. It's a lovely campus. Aside from the classrooms and lab facilities, Carlsbad has a small museum and a huge library. It's also minutes from the ocean.
Carlsbad is a big contrast to NYC. I used to travel to NYC weekly (pre-COVID), and it's hustle and bustle all business for me. I like the Carlsbad campus as it's so refreshing, and it truly puts me in a different place, my happy place! It puts me "in the moment", if you will. As I continue with the courses where on-campus work is required, I plan to fly to Carlsbad to attend.
So far, I have taken enough courses and received my Applied Jewelry Professional degree. You can keep going up the ladder, eventually getting your Graduate Gemologist (GG) if you wish.
Here is a link to the programs and tuition for Carlsbad, CA. For a GG, it's about $24K for Carlsbad and about $23K for NYC, so it's basically the same price:
Carlsbad - GIA.edu
As FYI, if you want to switch locations (e.g. NYC, London, HK...) go to the top of the page and select "Schedule & Fees" to see the other locations.
Colored gemstones is my true love (emeralds, rubies, ...). I would love to be a loose gemstone dealer and go to the Muzo mines of Colombia to buy fine loose emeralds, or go to Mogok in Myanmar to buy fine loose rubies. Of course I would not make any money as I would probably keep all the stones I purchased for myself!

I hope this info was helpful. I truly enjoy the courses, even if it's only for continued self-learning. I think you will enjoy them too.