I read a shoujo manga where the female lead falls in love with theatre and so she tried out for it but she just wasn't good at acting. She later discovers she's actually a good sscript writer and so she works in theatre being a script writer. Forgot this manga's name. Any clue?

It has been awhile since I've read it, but your description reminded me of Ashita no Ou-sama. Perhaps that is what you're looking for?