A haunting childhood moment defined how John Kakuk would think about investing his own money when the time came. During the 2008 financial crisis, his mother asked him if he would be willing to contribute the meager savings in his piggy bank to his family’s grocery fund should his father, a lawyer, lose his job.

“She was very anxious,” Mr. Kakuk, then 12, remembered.

His family averted disaster. “As far as I know, we didn’t miss a mortgage payment, we didn’t get a car repossessed, nothing like that,” recalled Mr. Kakuk, 28, who runs Bridger Digital, a marketing firm. But the rattling experience steeled the Montana native against the tumult caused last week by President Trump’s announcement of steep global tariffs.

In response, markets plunged, but Mr. Kakuk, who described himself as “notably invested,” said he felt little alarm about his portfolio, even if it took a few short-term body blows. On Wednesday, Mr. Trump announced that he would pause the tariffs for most countries for 90 days, and the S&P 500 swung in the other direction for its biggest daily gain since 2008.

“People my age are in a very different position from our parents when they were our age,” Mr. Kakuk said. “We don’t have a lot to lose. We just have everything to gain.”

Interviews with young investors — ranging from high school students to entrepreneurs in their late 20s — aligned on a variation of that theme. Helped in part by digital platforms with low bars to entry and enticed by the promise of cryptocurrency, members of Gen Z began investing at 19 — six years before the average millennial and 16 years before the typical baby boomer, according to last year’s Modern Wealth Survey from Charles Schwab.

These younger investors said they were willing to countenance risk — but also to hew to a keep-calm-and-carry-on investing philosophy as the market swung wildly. If anything, the plummeting prices led to discounts unavailable during the years when stock markets were on a relentless climb.