changing text colour in After Effects

When you are troubleshooting a problem the first thing you should do is start turning off effects. You have Glow and Emboss applied to the text layer. The Fill color for the text is dark red, the stroke is only 1 pixel. Turn off Glow and Emboss and you will see dark red text with a very thin green stroke that you can change to black. Because the stroke is only 1 pixel if the position of the horizontal and vertical edges of the text layer is not perfectly aligned with the pixel grid, the stroke is going to be antialiased and blend in with the background making it very hard to see. If you animate the position of the text layer the edges are going to flicker unless you introduce a fair amount of motion blur. Generally, if you are using a stroke it should be at least 2 pixels wide.

When you turn on Emboss you will see that the foreground color changes because of your settings. Emboss is probably not the effect you want to be using. Try selecting the layer and then going to the Layer/Layer Styles/Bevil and Emboss menu. You will have more options.

When you turn on Emboss the fill color is going to bleed into the stroke color. That is where the red edges come from. You may be better off using Layer Styles because you have color controls there. 

There is nothing wrong with your comp except the width of the stroke and the effect settings.