Americans are waiting longer than ever to buy their first home. And for many, it’s not happening until they’re middle-aged.

The median age of the first-time homebuyer rose to a record high of 40 last year, according to the National Association of Realtors, up from the early 30s roughly a decade ago. The average American today will get married and have their first kid in their late 20s or early 30s, according to Census and CDC data. Homebuying was once coupled with those milestones. But the housing market has grown increasingly unaffordable thanks to high interest rates and low supply, effectively reshaping the American life timeline.

And Zillow CEO Jeremy Wacksman doesn’t see that changing anytime soon.

“The fact that it’s been going up is this affordability challenge,” he told Fortune in an exclusive interview, referring to the median age of the first-time homebuyer. “People are having to wait longer to save up and find their way into a down payment.”

“We aren’t expecting any relief in the short term,” he added. “I think it’s just going to take a while.”