Under a pantry self we found two bottles of irish Creme Liqueur. They had been there, in a cool dark place for about four years- unopened.
Now if it has been hard liquor, I wouldn’t have a qualm.
But there’s the "cream or “creme” part.
Safe?
A Google search indicates good only for two years.
Cool and dark means you have the best possible chance at preservation past the suggested date.
Wait, is there a printed date somewhere on the bottle, or do you just know the approximate purchase date?
I guess swirl some in a clear glass under bright lighting - any discoloration? Good ol’ sniff test yield any data?
Dump it. The stuff isn’t expensive. Buy new.
The printed date will almost certainly be pessimistic. It will last longer than it said. This much longer? Well, bad dairy products stink like hell, and they tend to separate into solid & liquid too, so it probably won’t take too much testing to find out.
A cup of any kind of amber-coloured liquor with some cream and some sugar syrup added would probably taste better to me, but without all the evil preservatives you’d have to finish it fairly quickly. Not that that would be such a challenge. 
We’ve had a couple threads like this in past. Basically, you’ll know when you open it. Chances are that it’s probably past its prime. I’ve opened Amorula cream liqueur of about your vintage (looking at the old thread, it was five or six years) and it had gone chunky on me. It was very obviously not drinkable when a solidified cream part and liqueur part comes out of the bottle. Now, stored in a cool enough place, maybe four years will be fine with your bottle, but I’d bet against it.
ETA: Here’s what happens when it’s 20 years old. (I think this may have been a Doper who recorded the video. I seem to recall it from one of the threads I read about old Irish cream but haven’t checked exactly which one.)
ETA2: Yes, it was Enderw24.
Just to be a true Doper, I’ll chime in with “Why drink store-bought? Make your own!”
*2 egg yolks
1 pint heavy cream (could use half and half if you’re a candy ass)
1 can sweetened condensed milk
1 tsp. vanilla
1 tsp. instant coffee dissolved in 1 Tbs. water
2 Tbs. chocolate syrup
6 - 8 oz. Jameson Irish Whiskey (6 makes it smooth, 8 kicks you in the ass - your choice) or Bushmills
Makes just over 1 liter.
Pour into bottles and refrigerate.
Shake before serving.*
I opened them, one was funky, other seemed Ok, but just in case I dumped them both. :(:(:(