Speaking from experience, make sure you really want a Chanel brooch.
They are quite expensive now, especially for costume, jewelry.
I bought mine years ago (when the crystal ones were around $300-400USD), and I think I wore it once. I ended up reselling it. Since I had the original box and everything I was able to resell for 3x of what I bought it for. I was lucky. It was in perfect conditions with no chipping, discoloration, or falling out of crystals.
I realized that I am not a fan of pin holes in my clothes. I could probably get away with a material that has more texture like tweed, but I only have 1 tweed jacket that I've worn once. So I've realized that I am not really a tweed person atm.
I bought my mother a CC brooch a while ago as well. She rarely uses it and wears it on special occasions. Luxury is not her thing though so all the luxury I buy her she babies it because of the cost, so it is to be expected.

It is also full crystals, no issues probably because of little wear.
The brooches I currently have are a gift from my former Chloe SA that was specially made in France. It's a small C and I love it but I keep it more for sentimental value. Then I have a couple of non-designer vintage pieces that I like to collect.
Agree with
@880 , try out some cheaper brooches first to see if it is an accessory that you love and will wear often. And also echoing
@papertiger if you are set on getting one, make sure to get one with no crystals or pearls. Chanel costume jewelry is notoriously know for those things to fall out over time.