Travel insurance and age

I am going to visit friends in Greece for 1 week in 2016. The flight was very cheap and I have an EHIC card. My question is that I am 66 now and will be 67 when I travel.If I book now, will it be my age when I book or the age when I travel which affects the premium? I only need medical cover for anything not covered by EHIC.
One thing which also confuses me is that in the past I have EHIC but the insurance company never seems to ask whether you do which seems odd.
Many thanks