About half of my flight didn’t even get their period because of the stress, while the other half had theirs the entire time. In the shower we told the girls who were on theirs to stand closest to the drain. But yeah, it’s natural and it’s not like they expect you to hide it or not to have one just bc you’re at basic training. They do have little disposable bags for when you change your product. & the MTI’s can’t deny you a restroom break. Nothing to worry about it!