Question about gender ultrasound

Veronica • George Alek Jr 4/08/17💙 Layla Jae 8/16/2018💜 Currently pregnant due in November
I am 13 weeks on tuesday but will be 15 weeks and a couple days when I find out the gender at a private ultrasound place. I'm doing this at this time because husband will be deploying very soon after. How accurate will it be?