Go to court, throw yourself in its mercy. Mail won't accomplish much beyond just ending the proceeding. At your court session, explain that you never did get the first notice; that you were lost - basically, what you just told us. Your friend is right, chances are good you'll at least get your fine lessened, if not waived entirely. (still expect to pay court costs.)
Also, if you had out of state plates and are now a Virginia resident, you better walk into court with Virginia drivers license & registration. (Arlington sucks about enforcing taxation & licensing - ask me about my yearlong battle from across country sometime.)
I don't remember if Virginia has the "stay clean for a year, get this taken off your record" deferment option, but it might be worth investigating as well.