Depends on your hair face shape etc best advice is to research before u jump into it, i had mine cut diana style as wanted an easier style for me while being a new mum at the time, hairdresser convinced me to go for it saying i'd suit it & with my hair being fine would be much easier - oh how wrong was she
thank god hair grows, it didnt suit me my hair was not thick enough to take a short style - nitemare besides i looked like a boy too nahh yak, never again no matter how old i get!
I think its personal choice & you will never know till u try, but i dont think long hair is just for young people, like someone said as long as its cut well & looked after what does it matter, my family friend had hers cut shorter as shes suffering with MS & is struggling to look after long locks - but she definately suits it shorter
Again think it come to face shape, i have a long face shape so short styles exagerate that more where as oval & heart shape heads suit shorter styles.