I would say don't breed her. It is very stressful on a mare.
Is your mare a fine example of the breed(great conformation, bloodlines, and ability)? What did she accomplish in her life?
Thoroughbreds are not in short supply, and even the best bred ones are not selling well.
Is this palomino stud you mentioned registered? Is he even a TB? Do you just like him because he's yellow or possilbly easily accessible? Has the stud produced anything worth mentioning?
Have you ever trained a foal? Foals are VERY easy to spoil and that is VERY hard to undo, especially if you don't know what you are doing.
Personality and being sweet, or other silly things are not good reasons for anything. Breeding, selling etc. How many "sweet" horses are people having trouble GIVING away.
Color is also not a good reason to breed.
Go to a few auctions. Even if you are not going to buy. Just go, and ask yourself if you really want to breed. You could easily say, "Mine will never end up at that auction." but how does that help the ones you see.
I have seen TB colts by a stallion with a $10,000 stud fee not get a bid at a breed auction.