Severance agreement arrived, need a second opinion - first time posting

I was offered 17 weeks of severance after 17 years as a customer-service rep, and I have a few days to sign. I have read a lot of threads here and could not find my exact situation. There is a non-disparagement clause. Did anyone negotiate and succeed?

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.