Festival style outfit for 40 year old

[Eastereggfan]

I'm attending a summer party for DH work in August. It's a festival theme and it's military so not exactly cut off denim shorts and crop top type function. Not that I could wear them at 20 let alone 40. I'm size 10 5',5.
Does anyone have outfits for inspiration? Thank you.

Depends on weather - wet then jeans and wellies!!
Otherwise maybe 3/4 length trousers, sandals, vest top and some sort of Kafkan type top,

Argh yes good old UK weather. A kaftan style long top is an idea 🌝

Flowery dress and boots
Flowers in hair and lots of beads and bangles

Yes boots good shout and have a flowery dress, thanks.

If its sunny I'd wear a floral dress possibly with sandals, converse or some kind of hiking boot depending how much mud is likely. If wet just go practical with wellies fleece and waterproof.

Last time I went to a festival I wore jeans, boots band t shirt biker jacket and a leopard print scarf. It wasn't particularly warm that day but I was OK and felt comfy and like I looked nice!