I married at 25 and if I'm honest I sort of sleepwalked into it, even though we'd been together 4 years and living together for nearly 3. I never had the 'she's the one' thunderbolt, despite her being fit.
In many ways we're not a great match, have had a couple of temporary break-ups, and longer spells where one of us has wanted to kill the other. She's a fuckwit in ale and, after losing her dad and having her mum diagnosed with Alzheimers soon after, she sailed close to it taking over. I feel like I've had to hold everything together, and it's been fucking tough. I think going back a long time neither of us has particularly fancied the other. And both of us, I suspect, consider the other to be below us - for different reasons.
But we're still together, have some great times. She's over the drink thing (still changes personality when she has some, but that's not often now). Our financial position has become comfortable.
Our two kids are really clever, good looking, funny, athletic, confident, happy. And that, IMO, is the absolute crux. And also why I'm happy that we got married.