It's time to replace all tires for my 2013 Outback Touring. Just bought 4 Pirelli P7 All Season Plus from Canadian Tire but haven't mount them. Just found the manufacture date is 1216, which means the tire has been more than 1.5 years. I am wondering if this is acceptable since I heard the lifespan of tires are about 5-7 years even if you don't use it. Any suggestions on it?