I heard that certain people are more likely to get trisomy number 13 patau syndrome than others, why is that?

Child of older mom: Increasing maternal age increases the risk for chromosome disorders, highlighted by trisomy 21 (down syndrome) but applying to rarer trisomies like the trisomy 13 causing patau syndrome (1 in 8000 births or so). Risks for trisomy increase gradually with maternal age, going from <1 in 2000 under 30 to ~ 1 in 50 over age 40, with age 35 arbitrarily set as high risk (~1 in 200).

Yes: Due to a mistake in cell division; due to inheritance of the extra chromosomal material from one or both of the parents; increased maternal age, pevious pregnancies with trisomy 13.