I first started with desktop applications development. When I moved to databases full-time, I started in Oracle development and did have a mentor. She gave me to a developer who taught me a lot. When I reached his level, she took me back and she went nuts. She had been a DBA forever (loads of experience) and taught me so much about design and how things work; there was a lot but I loved it.
As for median salary, I don't know what it is, but since we're in the same metro area, I'm sure you do. If you know it, would you post it along with the source?
So, similar to Brandie I took a quick look at salaries in the metro-Detroit area...
Glasdoor reports ~$72k/yr for a SQL DBA, Payscale.com reports ~$101k/yr for a Senior SQL DBA.