Is it legal to date a girl who is 16 when I am a 19 year old boy? Is it still true that the age limit between dating is 4 years apart?

Where are you located? State and local laws vary. "Dating" is very broad. Sex is different.

Going to dinner and events is fine. Being alone together can cause you trouble in many places.

I think it more depends on the laws of her PARENTS or guardian more than what the state you live in says. So what do THEY say?

As noted, there is no real "law" on dating, at least in America, except that you can't, if the parents object.

Having sex, is not dating, and there are state laws on the age, issues