I did not find a common data set (CDS) for Olin. Look at MIT. Their male/female ratio of students is similar. The acceptance rate for men is about 6%; about 12% for women. All schools would like to have their pick of who they accept. Your stats put you well into territory for being accepted at Olin. They are encouraging you to apply so they (not you) can decide. Once again, the standards are not any lower for women, but there is more room for women who meet those standards than for men. They likely have the pool to draw from because of outreach. If they did not do this sort of outreach, perhaps fewer women would apply.
A personal invitation is simply an advertisement. It has no weight and really means nothing. As you get older American Express and other credit card companies will send you “personal invitations” from a vice president in recognition of [nothing] so that you can join the “elite ranks” of cardholders that carries some color-coded version of their brand. It is just a form of “feel good” marketing to make you aware of them and make you feel like they are elite, and, by extension, so are you.