to do with their job performance. Grades are not a great indicator either in engineering. Most are extremely smart. The best indicator I have found of the best engineers (MEs, though it applies to other fields as well) is what they do with their free time. The best engineers have naturally been re-engineering their toys, and tree houses, and bikes, and computer programs, etc. etc. etc. from a young age. They can't help but tinker and use the math and science as tools in the process. The engineers who are good at math and science and looking for a place to apply those skills can learn to be good engineers, but are usually have a much longer training time and don't seem to be as adaptable as the naturals.
Though it is almost taboo to say out loud, if she is a female engineer that is remotely proficient, employers will be lining up around the block to hire her and promote her afterwords. Some of the best engineers I have ever ever worked with are women, because they are naturally good and also because they forced themselves to be better in a field that is typically has more male graduates. Unfortunately, some of the worst engineers that I have worked with are also women that were hired over more qualified male counterparts just for the PR of having a female engineer in the company. I hope your daughter is one of the great ones!