Short Sundresses How Short Is "too" Short For A Sundress?

How short is "too" short for a sundress? - short sundresses

I have a summer dress and a cotton fabric to mid-thigh. I am 15 years old, 5'5 "and my friend told me that the dress is too short.

How to be long dresses of the summer? The knee?

And by the way, do you think the gray color is ugly for a dress?

Thank you.