I'm not sure hot that works yet. That may just be a mechanism so that you've got an up to date version, that they don't have people running years old versions or something. (Mine also had that expiration date even though I downloaded it in August.)
I wouldn't worry about it, we'll find out what to do in July I guess. Plus Microsoft is apperently going to start giving away anti-virus software sometime after the second half of this year. (In theory that's bad 'cause of antitrust stuff, blah blah blah, but I'm terrible-I love having all these utilities built in to the OS! I love Windows Defender, I love having free disk tools, etc.)