Yeah, you can shave or trim if you want. If you're expecting your period to start soon, I would avoid waxing. You don't want to start your flow during an appointment (embarrassing,) and if you're more sensitive then the waxing could be more painful.
There's no reason you can't shave or trim though. It may be inconvenient to do either during your period, but any other time shouldn't pose a problem. Groom yourself as you see fit. It's your skin you're living in. Your hair, your life, your choice. Do what you want.