The decision making part of the brain develops in mid twenties, hence making you more wary of the reality of life and setting your priorities straight. Before that most people are in college/not taking life seriously, having wrong ideas about what a high value man is (for example caring too much about looks), not having enough life experience, are impulsive, etc. Also due to being around people mostly in your own age range in college, you are more likely to date them, without having a clear idea of what level of success this man can reach.

Also after the age of thirty, your options become limited. A lot of people are taken, you may become more critical and less likely to compromise because you waited this long to settle with the perfect partner, you may have lost some of your youthfulness if you haven't taken good care of yourself/partied too much, your fertility is more likely to be affected, etc.

From 24 to 30, you are wise enough to know your worth and not settle for something that will have no actual benefit to you. You have enough life experience to treat a man in a good way, you have a job and have a more clear idea of your goals, you are in your prime lookswise/know what kind of wardrobe suits you best, and you are more likely to meet people who align with your goals.

I'm not saying that before and after this age range there is no chance to find your ideal life partner. But this is the golden window for most women, and they should use it wisely.