With a GATE 2025 score of 644 in civil engineering, an OBC girl from Andhra Pradesh has a good chance of getting a seat in structural engineering. However, the cutoff scores for structural engineering programs vary across institutions and are often influenced by factors like the number of applicants and the seats available.

Considering the candidate's score and category, here are some possible institutions and programs to explore:

- NITs: With a score of 644, she may have a good chance of getting into NITs like NIT Warangal, NIT Trichy, or NIT Surathkal for their structural engineering programs.

- IITs: Although the cutoff scores for IITs are generally higher, she may still have a chance of getting into some IITs like IIT Guwahati, IIT Gandhinagar, or IIT Hyderabad for their structural engineering programs.

- State universities: She may also consider state universities like JNTU Hyderabad or Andhra University, which offer structural engineering programs.

To get a better idea of her chances, I recommend using online college predictors like Careers360's GATE College Predictor .This tool can help her estimate her chances of getting into specific institutions and programs based on her score and category.