So you've already gotten the clear "no, white tongue often is NOT thrush" answer, but also you should look for the other symptoms of thrush to determine if it is or not. My baby had a white tongue too in the first few months and a doc at a pediatric hospital (I'd taken dd for a different reason) even looked at it and said "Yes, it's thrush" and called in the prescription for Nyastaton or whatever the stuff is.
But then I googled it and read about it and asked around, and there were NO other symptoms and sure enough, not thrust at all. It was so frustrating that a pediatric doc would misdiagnose like that, he didn't even ask me about any other sypmptoms, just said "yeah, thrush".
So... healthy milk tongue most likely, but if you've got pain or redness or other thrush symptoms clearly you should look further into it. No other symptoms... likely no thrush!