That has nothing to do with stalling. Stalling is when the engine shuts off because of a lack of power. Imagine letting go of the clutch in 1st gear. The car dies, or "stalls."
To answer your question, no, its not that bad for the car. It can affect the engine, clutch, and transmission as a whole, but nothing to worry about if it was only a few times.
To give you a little more help, try to feel the sweet spot at which the clutch actually engages and disengages the gear. Keep the car in 1st and slowly start letting go of the clutch (don't apply any gas.) Pay attention to where the pedal is when the RPMs start to drop a little bit; that's your sweet spot.
What you wanna do is give the car a little bit of throttle (press the gas pedal) and then slowly let go of the clutch pedal until you hit that "Sweet spot," and then KEEP it there until the car grabs.
I'm sure you know that already, but I've realized that a big majority of stick drivers don't understand that the clutch should be kept at the sweet spot until it engages. Most will literally let go of the clutch pedal and watch the car stutter and stall.
Cheers,
Chris