It isn't so much the last frost date that is critical rather it is the first frost date in the fall that affects your decision. That and the variety you choose. Different varieties have different days to maturity ranging from 60 to just over 90 days.
How many days to the first frost date? According to the internet that date is generally in early Oct. in Pa. Another factor is heat...potatoes will stop forming when soil temps hit about 80 deg F (27 deg C). When does that happen if at all in Pa.?
Without knowing the variety and specifics about your climate, I'd say a good guess would be it is well worth a try...but get it done quickly.