Is this OK to wear for a work-related Gala, where the attire is "festive"?

I get to go to a gala for my job (I'm volunteering at the event, as a means of being able to attend, so I'll be walking around a lot.)

I'm wondering if this type of dress is ok? It'll be indoors in a big hall, during May. I'm in the Northeast, so weather could be somewhat warm around 69°F–75°F .

If this dress is ok, then I'm thinking of wearing like a metallic clutch maybe, and some white heels maybe.

Also, do you think I should bring some sort of shawl to wear over in case I want to look a bit more modest?

Please provide some advice!!