i have an interview with local 602 washington dc steamfitters and need tips

im 17 and this would be my first job. i have been taking welding classes for the last year and a half and have a letter of recommendation from my welding instructor which i was told would help. I also have my osha 10 and quite a bit of nccer out of the way already so i was hoping those would help too. I am very nervous for the interview though as i have only had a few in my life and none infront of a panel of people, so any tips from anyone who mightve gone through the same interview process already would be greatly appreciated