Nanita, Bob does not stop by very often and this board offers free answers from professionals and knowledgeable amateurs. It is open for everyone to comment.
Regarding your question, if you look through the search feature of the board about painting bricks, you will see answer after answer suggesting that it not be done and reason after reason why it should not be done. One of the major reasons is that it is costly, messy and difficult to remove the paint. It is also difficult to keep clean and the paint is not a protectant of the brick.
It is your house and it is not against any code that I know of to paint your fireplace brick, as long as you don't try to paint the inside of the firebox, which is dangerous. That said, because of the difficulty in removing the paint, some people feel that painted brick does lower the resale price of a property since it becomes a maintenance issue. I wish you well in your decision.