Can a sext a 16 year old girl (I'm 18) (New York)?

the age of consent is 17 BUT over 13 can consent to sex with someone who is no more than 4 years older ---- it appears as though it is legal check i for yourself ---- its only about sex but as this is less than actual sex it should be ok but dont take anyones word check it out

Nope, not at all. That's considered possession of child pornography which is illegal.