"The girls are just as short as we are."
Translation:Fetele sunt la fel de scunde ca noi.
English unfortunately conflated determinants of height and length in this case. For some reason, it kept the „long” - „tall” distinction but combined the „short” - „short” one. So, in Romanian, „scurt” refers to length (e.g. a short walk) whereas „scund” refers exclusively and always to the height of people (a short person), poetic licences notwithstanding.
EDIT: listing the forms of these two adjectives for reference: scurt, scurtă, scurți, scurte / scund, scundă, scunzi, scunde
"Eu sunt ca tu ești." is not Romanian.
"Fetele sunt la fel de scunde ca noi suntem." is not Romanian either. Something more Romanian would be "Fetele sunt la fel de scunde precum suntem noi.", but this is longer and less used. Please note the inversion "suntem noi" (instead of "noi suntem").
Fetele sunt la fel de scunde ca noi. = The girls are just as short as us.
"ca" expresses the similarity between two objects, beings, ideas, situations, etc.
I VERB as you VERB. /// I VERB like you. = Eu VERB așa cum / precum VERB tu. /// Eu VERB ca tine. Examples:
I am as you are. /// I am like you. = Eu sunt așa cum / precum ești tu. /// Eu sunt ca tine.
I sing as you sing. /// I sing like you. = Eu cânt așa cum / precum cânți tu. /// Eu cânt ca tine.
I VERB as ADJECTIVE as you are. / I VERB as ADJECTIVE as you. = Eu VERB la fel de ADJECTIVE precum VERB tu. / Eu VERB la fel de ADJECTIVE ca tine. Examples:
I am as short as you are. /// I am as short as you. = Eu sunt la fel de scund precum* ești tu. /// Eu sunt la fel de scund ca tine.
I sing as loud as you sing. /// I sing as loud as you. = Eu cânt la fel de tare precum* cânți tu. /// Eu cânt la fel de tare ca tine.
*"precum" can't be replaced with "așa cum" here.
You're not wrong. „scurt/-ă” (pl. „scurți”/„scurte”) is indeed a Romanian adjective for short - when talking about determinants of length.
On the other hand, „scund/-ă” (pl. „scunzi”/„scunde”) is the correct adjective to use when using determinants of height. It even says so on the dictionary definition for the term! ( https://dexonline.ro/definitie/scund )
Now I'm not saying that you and your community aren't free to conflate the determinants of height (scund) and length (scurt) as happens in English (short - short), since languages are inherently plastic things and if it works for you guys then there's no real reason to change it. Just note that you are going against the grain of standard Romanian which has two different adjectives to deal with either case.