I’d stick with your current roommate - besides it being pretty unkind to her to change at the last minute out of something other than necessity, you could end up in a worse situation with a random roommate.
In the parent Facebook group for my D22’s school, I’m already seeing freshman parents talking about bad roommate situations - really mean girls making fun of their roommate, kids coming home drunk a couple days after they moved in, a kid who moved in first taking over 3/4 of the space in the room, etc.
A lot of random roommates work out just fine, but not that many become “best friends” and some are horrible. At least you have a somewhat known quantity!