There's a few younger options for marriage...Erik the Slayer for one. He's got to be in his early 20s at best, given the quest you have to do to get him. Either that or his father's an epic helicopter parent. Ysolda's always struck me as fairly young too, and same for a few other NPCs.

Guess it's mostly opinion-based, but.
Does anyone else have the same opinions?
Yes. There's no Khajiit or Bosmer NPCs open for marriage at all, which I know a lot of people have complained about. Then there's the fact that there's only one male Argonian you can marry and two female, and one Altmer female you can marry but no males. It makes sense things would be skewed for more available Nord NPCs, since they're the majority of the population, but you'd think Bethesda would have at least tried to include one choice for each race and gender. Meh.
As for me personally...having just met http://www.uesp.net/wiki/Skyrim:Erandur, my character is extremely disappoint that he's not open for marriage.

She'd go for it if she could, even if it meant friendzoning poor Erik. I'm getting tempted to resort to console trickery on that front.
I know that on the PC you can marry anyone you want with console commands, but for an Xbox player such as myself, I was wondering if there's any way to do the same thing? Thanks.
I'm afraid not.

Forcing an NPC into the marriage faction via the console is the only way to marry anyone you want. (With restrictions. Some NPCs you can't marry no matter what...General Tullius and Ulfric are two that I know of.)