No, that's good. Often I'll see people are doing an exercise they think is targeting certain muscles, but they aren't doing it correctly and getting what they truly want from it.

Overall what matters most is that what you're doing is making you feel good, mentally and physically.

Like anything, our bodies are fantastic at adapting to stress. You won't feel sore after a few weeks because you've adapted to the stress of the type of work out you're doing. If you modify it, or do a different class, that soreness will come back :)

Fit and lean is good, you just adjust your diet to that type of body type, and continue doing what you're doing!