@Paige208 Guests are sent notifications to review by Airbnb just as hosts are. There's nothing wrong with mentioning to guests that you'd really appreciate it if they took a few minutes to leave a review, especially as you are newish and trying to build up reviews. It's also a good idea to let them know that the review window is only 14 days,, which seems like plenty of time, but some guests seem to be unaware of this, and it's easy to forget if they don't do it soon after their stay.
More than one message from a host about this would feel intrusive and coersive to many guests and could easily backfire. They'll either review or they won't.