JMHO, at 16 years old, I would think that both she and you should have an idea if she is ready for college not an individual evaluator. Is she the #1 pitcher on an "A" level team, limiting opponents in most games to 0-1 runs a game, then she might be college material. Just go to any college website and look at their pitchers resume. Usually All Conference, All State, etc with ERA's less than 1.00.
As far as general ability goes, ask yourself if she has what it takes. Work ethic, composure on the mound, pitch command,etc. By 16, she should throw mid 50's and up, with 3 other good pitches, including a good off speed.