If her first year of playing professional golf in the United States is having any ill effects on 18-year-old Pajaree Anannarukarn, she certainly is not showing it.

The Symetra Tour rookie from Thailand owns four top-10 finishes in four tournaments, and she served notice Thursday that she's ready to challenge for her first career victory. She fired a 6-under-par 65 to tie for the opening-round lead of the Valley Forge Invitational at Raven's Claw Golf Club in Limerick Township.

Laura Wearn, a fifth-year Symetra Tour player from Charlotte, N.C., also carded a 65 to share first place with Anannarukarn.

Eight players were bunched 2 strokes behind the co-leaders, including Sweden's Jenny Haglund, the tour's leading money-winner after her victory last week at the Symetra Classic in Davidson, N.C.

A total of 48 contestants broke par in the first round over the 6,421-yard Raven's Claw course, and another 19 matched par-71. One of the subpar shooters, with a 70, was Hatfield amateur Isabella DiLisio, who just completed her junior year at Notre Dame and is playing on a sponsor's invitation.

Anannarukarn, whose best finish was second at the IOA Invitational last month, shot the lowest round of her brief Symetra career without carding a bogey. Of her six birdies, her longest putt was an 18-footer at the par-3 14th hole. She called the Raven's Claw course "challenging and kind of fun."

She moved to this country in March and will be staying for seven months. She is accompanied by her father, and her mother will be flying in for a few weeks next month, she said.

"This is my first year, so I've been learning a lot," she said. "I like it so far. This is my fourth week in a row. It's fun. I'm a little tired, but I have to keep myself fit and eat a lot."

Wearn, 27, is second on the tour in driving distance at more than 291 yards per tee shot, and she was happy she got to use the power a lot on Thursday.

"I liked the course a lot," she said. "It was nice to be able to hit some drivers and I felt like I had a lot of wedges in, so that was fun. The course is pretty open with a few quirky holes but it's a really fun track."

Wearn was 5-under going into the par-4 11th,  but a double bogey there set her back a bit. She rallied at the end with birdie putts of 4 feet at the 16th and 3 feet at No. 18.

"I was really happy about the round," she said. "I saw a lot of putts go in, which is nice because I've been struggling with my putter the last few tournaments. It was a big confidence booster."

Local notes.

DiLisio stood at 2-over par for her round on the 12th tee, but she birdied three of her last seven holes to finish under par. … Emily Gimpel of Lafayette Hill had a 78 and Ginger Howard, who has roots in Delaware County, carded a 73.

The results:

Pajaree Anannarukarn 34-31—65

Laura Wearn 32-33—65

Jenny Haglund 31-36—67

Christina Foster 33-34—67

Emma Henrikson 31-36—67

Demi Runas 35-32—67

Charlotte Thomas 34-33—67

Alejandra Llaneza 35-32—67

Jenny Coleman 33-34—67

Carlie Carr 34-33—67

Elizabeth Nagel 33-35—68

Shannon Fish 34-34—68

Youngin Chun 34-34—68

Linnea Strom 35-33—68

Desiree Dubreuil 34-34—68

Fatima Fernandez Cano 36-32—68

Pavarisa Yoktuan 36-32—68

Haley Mills 33-35—68

15 players at 69

Also:

Isabella DiLisio 37-33—70

Ginger Howard 36-37—73

Emily Gimpel 39-39—78