float Whatever_Your_Adjusting_Factor_Is = 0.5;
float Changing_Size                     = 0;
float Max_Size                          = 2.5;

if( (@age * (Whatever_Your_Adjusting_Factor_Is)) < Max_Size)
   {
   Changing_Size = @age * Whatever_Your_Adjusting_Factor_Is;
   }
   else
   {
   Changing_Size = Max_Size;
   }

@pscale = Changing_Size;