This is because of the natural accumulation of experiences over time.
Older women are more confident than younger women, because they know themselves and the world better. Perhaps most importantly, they are not afraid of men, so their inhibitions in a man's presence are less severe.
I've dated countless women and it has always amazed me how little they know about men.
The following is the article from Myanmar Man’s Diary blog republished with permission.
Burmese law allows Myanmar citizens to get married to a foreigner. Today, no judge or local court would marry a Burmese and a foreigner.
Even after you get married, your marriage certificate (actually a marriage contract in Burma) is in Burmese language. You can get a certified notary translation of your marriage certificate into English but the Foreign Office will refuse to certify that notary.
At most, it is a reliable source of advice for women who want to improve their chances with the opposite sex.
I spent about a year dating almost exclusively women older than myself.