Formal party hair!? plz help!?

tomorrow is the yr 6 farewell party for my school. i'm 14 years old (repeated twice) and not very 'girly'.im know as a tomboy. i stink at doing hairstyles and my usual hairstyle at school is either a pony tail or a bun. my hair is about 12cm past my shoulders and is dark dark dark brown. i dont have a fringe or layers. (sound like boring hair eh?) it is natually straight but has turned wavy due to using elastics everyday in the same hairstyles. i have a straightner (that unfortunately CANNOT make curls). i dont have a curler :(. i dont have many hair supplies;just bobby pins and hair elastics. i cant go to the hairdresses because i wont get there in time. my dress is a halterneck dress that's brown, blue and white (summer dress) im wearing black heels and wearing NO jewerlly (because i havnt pierced my ears and the shops are closed) . im wearing just lipgloss. im just worried about the hair i was going to wear. plz help