A jiffy bag jb chan 144 155 180 Furthermore, a woman's average age at first marriage is the highest it's been in over a century, at nearly 27 years old. "The age at first marriage for women and men is at a historic highpoint and has been increasing at a steady pace," states Dr. Wendy Manning, co-director of the center. Most US men wait till 28.9 years of age to tie the knot.