Thinking of starting a blog related to yoga and software & throwing on adsense. Wondering...

1) Is this a decent niche. Should I even expect to get any $ from it? Of course I'm assuming that I put on good and fresh content, etc.

2) What is normal per day amounts for everyone, and also if you reply, how long have you been going at it? I just want to be realistic about the $ and know what I'm getting into.