Am I healthy or underweight? I am a 28yr old female, 106 lbs, 5f 5in, 17% body fat which is considered fit.

Probably. The answer really depends on if you are eating correctly, exercising adequately but not excessively, and if you are feeling good. Everyone should maintian the right amount of food and exercise appropriately. If you're okay with all this, then your weight is probably okay.
Well. I calculated your body mass index at 17.6. Below 18.5 is underweight. It may be due to low muscle tone but some people are built thin. Eat well, it doesn't sound like you are too concerned. You are considered underweight by using a bmi calculator. It doesn't necessarily mean your unhealthy. Good luck.