Would InDesign be the program for creating graphic novel layout?

From what you describe (illustrations produced), InDesign would be perfect for assembling a multi-page document for printing and digital formats. You add the front matter, the folios, add the illustrations on each page, create a separate cover, if it's to be printed on heavier stock. Job done!

Are your images in a standard 6- or 8-panel layout--or are they in the size ratio needed for your layout design?

What program did you create the images in?

Are you planning on printing the novel or just creating a digital version?

There is a faction that came to use Illustrator for full page layout work, even text-heavy layouts, more or less in the days when actual page layout apps were more limited. I can't really recommend it as an option for new work/new skill learning except for — maybe — a few extremely complex pages at a time such as ads or high-end brochures.

InDesign is the tool for doing complex page layouts, and has at least basic versions of the features Illustrator and Photoshop provide. If you need high-end vector or image tools, the Adobe set makes it easy to integrate work from those apps in InDesign.

I am assuming your goal is print; be sure you start with a selected printer or PoD service guidelines and work backwards to define your layout, image quality and color model, etc. Otherwise you'll get poor results or have to rework the layout to suit the printer's requirements.

If export to e-book is in the cards, there are more guidelines to follow, both in general and for each selected format/provider. In general, for e-book export you have to keep your file meticulously organized and formatted; you can't get away with sloppy practices and "sticking stuff on the page" as you can for print.