Im not 100% sure, and with all the crossbreeding i dont think anyone is, but I do think its a red variety. Most of the red plants have inverted "scalloping" on the edges of the stems, the area between the thorn points. Meaning they dont roll out from thorn to thorn, they curve in. The amount of the curve varies from species to species, just like the outward curve varies on the pink ones. If you've ever seen a mature and healthy American Beauty plant, you'll know what Im talking about. The yellow Megalanthus variety also has inverted scalloping, but the thorns on that one have a very distinctive single point, and a wooden quality, much like rose thorns.
I dont mean to discredit whoever told you the details about your plant, btw. Im more concerned about whether its the only variety you own, and if its not what you were told it was, that you have the means to pollinate it once it flowers. Reds tend to be self sterile, or fussy when they aren't. Too many people wonder why they never get fruit after tending to these plants for years, only to find out it's because they need a pollinator. As a general rule, I advise people to never grow just one type of dragon fruit. Even if you are limited in space and need to run two plants up a single support, its always better to make sure you keep your options open.