19 year old boy dating 15 year old girl?

This isn't a question of morality. I personally don't care about the age gap and she doesn't either. I really like this girl and she really likes me. We don't plan on getting sexual, but we do want to date. We're going out this weekend and she wants me to pretend I'm 17, but I just want to come clean and just tell her parents I'm 19 before they find out on their own. I feel like if I talked to her parents and explained my intentions beforehand that things would go better. I've also thought about pretending to be 17 for like a month until the parents warm up to me and then tell them. Basically, I want to know what you guys think is the best course of action for me to take to make this work out between us.