This is 20’s and not flapper. More tea party and might be too tame for a night party.

Belle Poque Vintage 1920s Dress Victorian Titanic Maxi Dress Tea Party Gown Antique Dress https://www.amazon.com/dp/B077GLQ2PM/ref=cm_sw_r_cp_api_glt_i_BD47ZVVP0617SVQHRM36?psc=1

And here’s an article about specifically not flapper 20’s fashion. I love the Earhart styles and the coco channel trousers.

https://vintagedancer.com/1920s/non-flapper-1920s-outfit-ideas/