Molly McNamara won’t attend her first class at Farmingdale High School until September, but when the middle school student is on a varsity field, she’s certainly accepted there.

McNamara played in her first varsity playoff game for Farmingdale on Thursday, but you never would have guessed that based on her performance. The eighth-grader had six goals and an assist to lead host fourth-seeded Farmingdale to a 16-11 victory over No. 5 Oceanside in the girls lacrosse Nassau Class A quarterfinals on Thursday.

Although it was her first postseason game, McNamara didn’t enter with nerves.

“I had a lot of confidence,” McNamara said. “I wanted to stay positive. I wasn’t really nervous because I know it’s not good when nerves get to me, so I just tried to come out strong.”

McNamara was especially strong to open the second half, scoring two goals over the first four minutes of the third quarter to give Farmingdale a 9-5 advantage. The Dalers outscored Oceanside 6-2 in the third quarter to take a 13-7 lead into the final period.

Farmingdale (5-11) advances to play top-seeded Massapequa (10-7) in the Nassau Class A semifinals at Adelphi on Tuesday. Oceanside finished at 8-7.

Regan O'Connor had four goals and an assist and Jessica Reo had four goals for Farmingdale. Julianna Roberts added two goals and three assists and Juliann Brzeski had two assists and seven draw controls in the win.

Farmingdale was coming off a 13-8 non-league victory over Locust Valley on Saturday, which aided the team’s confidence heading into the playoffs. The Dalers, playing in Nassau Conference I in ability-based conference alignments, only won one conference game this year, but they knew those contests against the best teams in the county would help them in the postseason.

“After a tough season, we really put everything together today,” O'Connor said. “That really made us who we are. In this game, it really strengthened us, and we’re very happy with this win.”

Oceanside took a 3-2 lead after the first quarter before Farmingdale outscored Oceanside 11-4 in the second and third periods. Kaylin Harrington and Sydney Abbott each had three goals and an assist for Oceanside.

Farmingdale lost to Massapequa in last year’s Nassau Class A final and fell to the team during the regular season. The Dalers haven’t forgotten those feelings between the two rival programs in nearly every sport with their schools separated by just five miles.

“We’re going to come out and surprise them,” O’Connor said. “We’re going to put everything together.”