I don't see what the age of the earth has to do with evolution, but you could look at it this way, evolution of itself is simply theory. It cannot follow through with the scientific method, therefore it cannot be proven, even if it were to be proven one day who's to say that that's not how God developed the living beings on the earth? As for the age of the earth anything is really possible I think. The bible never tells us how old the earth is, any timeline written in study bibles are complete guesses and no one really knows for sure.