My thoughts:
- It doesn't seem like your depression / anxiety is currently well controlled, and usually mental health issues will only get worse during medical school and beyond. If this is true, then you need to be in a good place mentally before starting this process.
- It will realistically take 10+ years before you are an independent practitioner. Are you okay with potentially losing this time with family, friends, etc.
- Any chance that this is currently a mid-life crisis? Wanting to help others is great and all, but really, there are so many fields in medicine that will allow you to "help others".
- Have you explored these other paths to see if they are a better fit for you? PAs for example are given a great deal of autonomy and do not require anywhere near as much training as a MD/DO. Similarly, RNs, PT/OT, Social work / case management, etc all play a crucial -- and many times, greater -- role in a patient's health and recovery.
If you've thought this through and are ready to take a plunge, then 37 is not too late to start by any means. Good luck