I am a truly decent guy. I don't want to be a thorn in their relationship with their daughter. Peter Peter, she has parents who, right now, have a problem with the age difference. You want something to change their minds. Only time can prove your good intentions and good character.
Time is the proof of all things.
Give her parents time. They have legitimate concerns. Their daughter is on the threshold of life's possibilities. They don't want life choices closed to her because of a man. A man who may be gone next month.