First layter thickness on mesh causing problems
 

So I am new to Fluent and have been thrown into the deep end with a project involving CFD with no experience using this before hand.
I am currently doing a validation study on a naca 0012 profile with a Reynolds number of 6 million and I have calculated the y1 distance to be 0.00015m to get a yplus value of 30. I am using a C-mesh with the free face mesh setting on all quad to save time on generating the mesh. I have used inflation to make the mesh finer around the airfoil and set the first layer thickness to the y1 value and then set the maximum layers to 20 and growth rate to 1.05. the max face size is 0.1, min face size is 0.01 and the curvature normal angle is 10 degrees. these settings produce an extremely fine mesh around the airfoil however I get a blue question mark next to the mesh in the work bench and cannot use in in the solver. using a value of 0.005 as y1 generates a good usable mesh however I am confused as to why this works when the value is so much larger than the calculated y1 value.

I have attatched the file of what this mesh looks like.

in addition to this I was informed that the most important value for the simulation is the Reynolds number, so I have changed my dynamic viscosity to reach the required Reynolds number of 6 million, am I correct in doing this even though it alters my y1 value?

and my final question is how do I check the number of cells in a mesh, is it under the statistics heading called elements?

I apologise if any of these questions are trivial but the guidance given to me by the university has been very poor and I would greatly appreciate any help with this.