Congrats on graduation! As far as meeting with the elders, go if it keeps peace. A close friend of mine was in a similar situation with dating an "unbeliever". She listened to their counsel and told them she would consider it thoughtfully.
The one thing you don't want to do is allow them to make you feel guilty and confess to anything. They are either looking for dirt or trying to save you from yourself. Neither is necessary. If you choose to marry "out of the truth", expect your marriage to be shunned by the witnesses and family that are still in the lie. A good reason to go away to marry, maybe a nice trip to the Bahamas, Virgin Islands, etc.