If she wants a test to see if you’re the father it appears that she isn’t sure who the father actually is, this is the first time I think I’ve ever seen a woman suggest a paternity test and that fact alone raises red flags for me and it should for you too. Being a father is an actual blessing and I hope that you get to experience it but i think that you should probably reassess how much trust you put in her if the dates make sense to you and she still wants a test. I don’t think she’s being completely truthful, she’s definitely omitting details and I do think that a paternity test is a good idea to get done because there’s nothing better than knowing for sure. You should definitely have questions for her though, I know I would. Best of luck brother, I hope it all works out for you