I have granted Q2 visa from Oct 2017 and did not entry to China, and planned to have first entry on

I have granted Q2 (2 years mutiple entry visa) from Oct 2017 and did not entry to China, and planned to have first entry on May 2018, will the entry permit still valid? i heard there is 3 months entry criteria once you granted the entry permit, is this applied to Q2? Thanks.