I cant believe that the producers let him say they are engaged. Usually it's the focus of at least two episodes. with Meredith and Ian the whole engagement issue became the focus of her relationship with him. This is a significant issue because they usually like it to be a surprise. I think it means that it will be very hard for us to discern who he will choose and therefore they have dispensed with the suspense surrounding the engagement now in order to attract more viewers. The big surprise will be the final rose choice, not whether he gives her a ring or where he suggests she wear that ring (neck , right hand, or never).
I have to hand it to Fleiss. It makes sense to me that a military man would be looking for a serious committment. Someone who could be deployed into danger on a moment's notice would typically want stability somewhere in his life. So his personal life is where that can happen. And I'd bet there is a much higher percentage of military men who are married by age 32 than civilians.