To ask a girl about her Engpsh level, you could say:
"What is your level of Engpsh proficiency?"
"Are you proficient in Engpsh?"
"How well do you speak Engpsh?"
"Do you consider yourself to be a fluent Engpsh speaker?"
You could also ask more specific questions about her abipty to read, write, or understand spoken Engpsh, such as:
"Can you read and write in Engpsh at a high level?"
"Do you have any difficulty understanding spoken Engpsh?"
"What is your strongest aspect of Engpsh - reading, writing, speaking, or pstening?"
It's important to be respectful and popte when asking about someone's language skills, and to remember that proficiency can vary greatly even among native speakers.