The above translation seems fine. ”並ぐらい” is usually used when talking about food. I might translate it something like "She's a 5 out of 10" or "She's got pretty average looks"... probably not best used when the girl is in earshot.

the most popular usage of 並 is about size, average size, so it turned to the meaning of middle degree. The you may hear the word most is in Yoshinoya (beef bowl)! If it used about people's appearance it means also "average". It's pretty rude though, better not say it.

it is... She looks ordinary doesn't it?