I have started recording all conversations I have without telling anyone. I am older with health problems. Get a digital recorder with a good microphone, something that works to 40 feet and you can put it in your pocket and still capture the conversation. They usually have a USB connection you can just quickly plug into your computer and download each conversation afterwards.
Make sure you document as much as you can in writing. Send emails to your manager detailing what you are currently doing, any issues you are having, etc. Anything you can put in writing to document what you are doing can be helpful.
Age discrimination is against the law. If you are doing good work, document that. Don't get upset at anyone. Recording yourself will keep you on your toes as you are speaking with anyone to make sure you are level headed in all interactions. If you are being lied to or harassed, you will have what you are being told recorded.
I strongly suggest recording everything.
Taken from @VuFtdEk-1zov
Anyone have any other suggestions for beating back harassment?