When I do my CPR certification for work, you have to take a short class and get certified. Your certification runs out and you have to redo the class every year so that your CPR certification stays valid.
I think you can learn CPR and it not be certified. Like if you learn it from a book or the internet or someone who is certified but not a licenced teacher. Even though you may know how to perform CPR, if you did not learn from a licensed teacher you can be sued if it fails. At least I think you can.
There have been lawsuits filed against people that were licensed to perform CPR. One such instance a man actually had his life saved by CPR, but tried to sue the guy that performed for giving him HIV. Turns out the guy that saved his life was HIV negative. (obviously the lawsuit got thrown out) Talk about an appropriate thank you huh.
But yes, I would stay with her and call 911.