That's true, there is conjecture about the age difference between Our Lady and St. Joseph.
While it isn't something that haunts my mind, if a gentleman is looking for a lady to give him children, then isn't it also fair that she look for someone with whom she can grow, spiritually and emotionally, as well as age-wise? I don't know about you, but I love to see the couple who have been together for many years, are parents and grandparents, and still have that love-light in their eyes. Is it too much to ask to want to give and receive that sort of love myself, someday? If it is God's will, then I will. He gives us a heart that yearns for love for a reason, so I believe that He is keeping me for someone special, and vice versa. God is Good.