If it's in good condition, and you love it, and it goes with the style of the rest of your house, then keep it. Have you seen this houzz article?

https://www.houzz.com/magazine/what-goes-with-a-redbrick-fireplace-stsetivw-vs~30186145

i am 100% certain that the next people who move into a house with a tiled-over brick fireplace are going to be asking 'how can i get the "ugly tile" off of my brick fireplace. 100% sure.

great link, smileyface, i remember reading that article. we have a red brick fireplace at our vacation home, i paired it with blue, i think its a great combo.

We have done this type of project, and the results were spectacular! Here is a link to the before and after on our blog:
http://edgewaterstudio.com/refreshed-fireplace-with-art-glass-tile/

The most important thing to consider, is whether the colour schemes you have throughout the room will still look the way you love them if the fireplace changes. There are many colours of tile we carry that can remain in a neutral palette or use a colour drawn from your brick, but colours like blue can also be an option that help to revitalize a space while being easily compatible with other colours.