Honestly, the fact that your family and friends wont like it or that if anything was to happen you could go to prison shouldn't be deciding factors here. You are a grown man, why are you even interested in a relationship with a child? Yes, a child. One who clearly isn't mature enough to know that beginning a relationship based on a huge lie is a completely stupid and immoral thing to do. Get out of this unhealthy relationship, cut contact entirely and meet someone who is actually on the same level as you. There is a huge difference between 15 and 19, mentally and emotionally. If you were to pursue any type of relationship, in person or online, you would be taking advantage of a vulnerable person.