Yes, keep them seperated. Nothing to really do for her,except put up with her PMS LOL. When the red color turns a straw color is usually when they are ready to accept a male. Also when she stands in front of him & flags her tail as if to say "cmon big boy here I am" make sure they can not get to each other. One of my little studs will whine & howl almost all night long when any of my females are ready. The sounds that come out of him are so funny but also a pain because noone gets a full nights sleep.
Also don't depend on panties or belly bands. I had a litter of 5 a few years ago with the panties.
Good luck.
Your little irl is now a woman. LOL