I have thought about rhinoplasty, facelift and now I think chin reduction. What do you think would improve my face most?

While only a face to face consultation, with frontal, tangential and side views can allow a full evaluation of what may be improved, your photos show a very fit, athletic appearance.  I see no reason for a facelift, as your skin has no redundancy, your jawline is smooth and straight and your neck contour youthful.  Some minimal facial fillers to add volume restoration to your face/temples would likely be helpful, as everyone loses volume in their face as they age.   Side views and measurements would be best to evaluate your chin and nose for possible refinement, although my feeling is only minimal, if any contouring should be considered.  See a board certified plastic surgeon for a detailed consultation.

From the photographs, it is difficult to advise you. Chin reduction and most of rhinoplasty provide profile improvements; therefore, these areas are best examined using a side view image. Your face does not strike me as droopy; rather you lost facial volume. I would recommend a personal consultation with a facial cosmetic surgeon in order to understand pros and cons of these procedures. 

Before I answer your question, I would like to say that it is wonderful to see the happy photographs that you have sent, and the happy children with you.  Regarding what I would advise you to do surgically:  it is always up to the patient: we plastic surgeons simply provide information so that you can make an educated decision, because ultimately it is YOUR aesthetic and YOUR face that you will live with for the rest of your life. In looking at your nose:  a rhinoplasty could help feminize your nose.  The trick is to make the rhinoplasty look natural, because the moment a patient looks "done," the patient looks old.  The same is true of a facelift.  It is all about natural beauty. Regarding your chin:  without proper photos or a consultation, it is difficult to offer an opinion.  I suggest you find a board certified plastic surgeon with years of experience.  If you can not arrange for an in-office appointment, many of us conduct Skype of phone consultations.  Please research your potential surgeon carefully, reading reviews, checking his/her educational background, and looking at before-and-after photos.