Possibility of having a multiple birth?

Yesterday I took a pregnancy test to my greatest joy it was positive. I announced it today to my twin sister who has triplets ( naturally concieved) now I always heard it skipped a generation, but it didnt happen with her, and there are some twins in my family ( maternal grandma, cousins from both sides). My sister said that when she first took her test, her pregnancy line appeared right away, before the control line... when I took MINE both lines were visible within seconds... I was 13 dpo when I tested so I'm wondering is there a possibility my hormone levels were higher because there is more than one? Or because the date when I tested?

Has any one had a similar situation (lines showing dark imediately) that resulted in multiple birth?