Guys in their 30s & 40s, will you fall for a gal in her 20s, and have a serious relationship with her?

I think most guys like younger women. The important thing would be that she is ready to settle down and not be into partying and running around looking for attention. One difference between older and younger women are that older women tend to be more attentive and giving, looking outside themselves more, while young girls still tend to be more about themselves and focused on what makes themselves happy. Also upon approach, older women tend to be more respectful. If they aren't interested, they will be considerate in how they respond, whereas younger women can be inconsiderate, so if you are kind and a giver it would be a big plus.