SPRINGFIELD N.J. — Three weeks ago, Rose Zhang called her first round as a professional, in which she shot 2-under 70, "moderately casual." 

Now, the 20-year-old is making her first start in a major championship as an LPGA Tour member — but the vibe is a little — or a lot — more intense than it was at the Mizuho Americas Open. 

"I don't think any round at a major championship is casual," Zhang said after an opening 1-under 70 at the KPMG Women's PGA Championship. "I definitely had to grind out there. I will say it was pretty much like a roller coaster. I feel like I was pretty steady in terms of my mental and pretty calm down the stretch, but the game did not look easy, and it did not feel easy."

Her spot on the leaderboard, however, might suggest otherwise. The former Stanford star sits one stroke off the opening lead at the historic Baltusrol Golf Club. 

Zhang, of course, did the unthinkable earlier this month at Liberty National, just 14 miles from Baltusrol, becoming the first female player to win in their pro debut since Beverly Hanson in 1951. 

In just one LPGA start this year, Zhang has already exceeded expectations. However, she's still hungry for more accolades, despite treating this season as a learning experience. 

"I definitely feel like there's a balance in between both," Zhang said when asked if her Mizuho win added or alleviated pressure for the rest of the season. "I always have high expectations for myself in terms of my preparation and how I'm supposed to perform, regardless of what my position is or what place I finish. 

"I think that — I don't have any expectations when it comes to the rest of the season or what I'm going to do. It's more so just learn. I treat this entire year as a fresh rookie year where I'm trying to learn as much as possible and navigate myself in this real professional world."

Zhang is no stranger to emerging victorious in prestigious events. She won the 2020 U.S. Women's Amateur, the 2023 Augusta National Women's Amateur and is the first woman to win consecutive NCAA Individual titles (2022 and 2023). 

Playing a major at a venue like Baltusrol, though, is a different animal from what Zhang has experienced — and in her young career, she's taking notes from those who have achieved glory in the sport's most prestigious events. 

"I was playing with (major champions) Lexi [Thompson] and Minjee [Lee], and these are people that I've watched on TV since I was younger," she said. "Just understanding how they do things and how they operate, I'm just learning along as I go."

Despite not even being of legal drinking age yet, Zhang already has a grand resume, which is why she's near the top of the leaderboard after 18 holes at Baltusrol. 

"(Today was) nothing that I didn't expect," she said. "I knew when you're going to be out here, it's going to be very difficult, and you're going to have to try to claw your way back when things aren't going your way. 

"These are all things that the game of golf has brought me and taught me in the past couple years."

Though this week's task might be more grueling than anything she's faced, it's not crazy to think that Zhang can again put herself in rare air on Sunday.