There are still a lot of question about Paragon 2.0 system although community Manager Lylirra and Travis answered a lot of questions about it. You can read more at Diablo III Paragon 2.0 Frequently Asked Questions. Lyrilla make a detailed answer about another point which would easily get players confused. Only Max Level Character Able to earn Paragon Experience after the expansion goes live. If you do not decide to buy the expansion Reaper of Souls, the standard of Max Level is different as well.
Level 60 would be the Max Level of those who do not buy expansion ROS. And they would earn Paragon Experience when they complete level 60.
Level 60 would be the Max level of those who renew their account with ROS. They would start to earn Paragon Experience when they complete level 70.
One thing still not answered is that would the Paragon Icon we earn when we get paragon level 100 gone. I mean, we should have some identity as we have invest so much time to earn it.