I am not a neuroscientist, but I do know that saying depression is caused by a "chemical imbalance" is a gross oversimplification at best. The human brain is incredibly complicated, and we don't understand nearly as much about it as we might expect, given all the amazing things humans have explored and discovered. Do antidepressants work? I don't know, but I've had enough success with mine to keep taking it (not an SSRI, for what it's worth).

I do think therapy can have a huge impact on how your brain functions and how you interact with your environment in order to feel safe and get your needs met. Your brain is astonishingly plastic and learning changes its structure and function. That being said, I would be cautious about ditching medications in the advice of somebody you just met, especially if you haven't talked to whoever prescribes the medication too. Of course it's your choice to determine your own treatment, but it seems prudent to maintain healthy skepticism all around.

If you want a neuroscience-based explanation of depression and how various treatments and experiences impact the neural circuits implicated in depression, I highly recommend reading The Upward Spiral by Alex Korb. It has helped me understand why certain things you're "supposed" to do for depression work better for other people than for me (and vice versa).