That's just fine. Nitrogen inflation is mostly a scam unless it's free. POA (plain old air) is mostly nitrogen anyway. There are valid reasons for nitrogen inflation:
1. High end race car drivers use it because it's guaranteed to be dry and so the pressure increase with heat from operation is very consistent. This helps when you're trying to tune the suspension for that last 1/100th second in lap time.
2. Low end racers use it because many small tracks don't have electricity (or water) in the pits and nitrogen is as cheap and safe as anything else.
3. Underground mine vehicles and subways use nitrogen because in an enclosed space the nitrogen doesn't add to combustion should a fire break out. High altitude airplanes use it for the same reason. There is plenty of oxygen in the atmosphere to support combustion, so for vehicles operating above ground there is no safety advantage.
The best thing about nitrogen inflation is that it does no harm if you don't have to pay for it. Also if you go to a place that charges for nitrogen inflation, you can be certain they also promote other questionable practices.
What nitrogen inflation doesn't do:
1. Make the tires run cooler.
2. Save energy.
3. Improve tire life.
4. Reduce sudden deflations.