I believe it will still turn blue...maybe less w/out light and heat but it seems most had a shelf life.
Don't know who produced your hologram or if an original one, but there was a time some years back where some of the new holograms that had been put away went bad. Some turned red, some black-ish, and some that went to goo. One belief was that the plastic the hologram came in had some adverse effect on it. No rhyme or reason.
I had a new one that I had stored in a closet. After reading about the news of them being ruined I checked mine. It was fine but there was an odor like the old 'toner' you had to put over a Poloroid picture....depending on how old you are you may have no clue what I'm talking about! ; )
I think I would just enjoy till if and when the time comes it goes bad. Just my 2 cents. Best of luck w/it.