Chances of Getting into a Top PhD Math Program
It depends on the definition of "a top grad program".

I think your GPA is good. GRE is usually not a (big) factor. I would expect most applicants to have >85/90%. If you are worried take the test as soon as possible. You can choose to send only your best result at the end.

Graduate courses are good only if you get good grades from them.

Try to make sure you get at least 3 strong recommendation letters by the time of the application. You want them to be from your field of interest. At least one should be from a more experienced faculty.

Also if it is possible try to get some undergraduate research experience. It helps, but it is not necessary.