I have an underage girlfriend...

So hey y'all,

I am currently 19 years old and I have a girlfriend who is 16 years old. We really like each other, and we would like to take it to the next step. But since she is underage, I don't know what the consequences would be. Maybe we will break up, and out of anger she'll tell the police that I slept with her, so I don't want to risk it. Any suggestions on how I should handle this?

Thanks