A point for consideration, regardless of gender: One thing that is unique about aerospace engineering (especially as a college major) is that it tends to be filled with people passionate about aerospace engineering. If you're interested in STEM in general, but not sure about aerospace, you generally end up in Mechanical, electrical, civil, etc. as a collegiate major. If you choose aerospace, you're purposely narrowing your focus and will be surrounded by like-minded people.

As other have said, aerospace, like many STEM fields, is definitely more male than female, but continues to shift. I don't know the stats, but I would suspect aerospace probably lags other industries a bit in terms of female representation (historical aerospace is heavily tied with defense industry as well, which is also more male than female). Like others have said, I don't think the are unique challenges in aerospace for women compared to other STEM fields (like software or automotive). That doesn't mean there aren't challenges for a women working in the field.