Well darn, Mimi! Joint replacements are not fun. But on the other hand, they are usually very successful and the pain and trouble is well worth it. But you aren’t there yet.
The O-doc’s exercise advice is good. Strengthening those muscles means the joint is better supported, and therefore there will be less pain and you may be able to put the procedure off for a while. But if the pain gets bad (as in, you have to medicate for it a lot), just have the thing done. The short-term pain is well worth the result. Kind of like having a baby! Well, no, not really. Babies are cute.