This is a question for the District Justice of your choice. I am from PA and I have no idea at all about Nevada laws other than to say that trying to work around them is a bad idea. We all expect the police to have perfect knowledge of all laws. If they did they would be lawyers not cops. Lawyers make more money and get shot at a lot less.
When you get into the nitty gritty legal hair splitting stuff like this you are most certainly going to run into a cop that is not aware of the subtle nuances of the laws of the two states. This could easily end up with you sitting in a jail cell trying to find a lawyer that understands the gun laws of the two states. You will need him because the DA and the judge may not be aware that what you are doing is completely legal. ( If it is and I sort of doubt it. ) If you happen to get a hard case judge even then you may end up working on an appeal between horizontal wrestling matches with your cell mate Big Pookie. You are an adult now. No Juvie for you.
Sure eventually you will prove your point and get out with all apologies... Maybe. Then instead of paying off student loans you will have legal bills to pay off. Legal debt can be larger than student loans.
You are better off to wait the three years. 21 will come.