When is it okay to send an email?

My application has been "on review" with Park Operations and Challenge Park for cashier/ticket taker since Monday.

Should I wait a few more days or go ahead and send an email to someone? I'm definitely interested in the job. I just have no idea how long a "normal" wait time for being contacted for an interview is, so I don't want to be rude by sending an email too soon. (And to which person would I even send an email?)

You should call them on monday. ask to speak to human resources then tell them what department you want and they'll transfer you to that manager then you'll probably get an interview time from there