Marriage issue | Parental pressure | Need honest and genuine suggestion

If you both are adult (above 18 and 21) and if she has no hesitation. Convey both of your message politely to her parents to get in wedlock. Else go for registered marriage. 

Parents have every natural rights on their children. Whether they live under the same roof or not, parents have a moral duty to give honest advice to their adult children; they also provide wonderful company to the grandchildren. Educated and enlightened children never miss out from parental wisdom, although at the end of the day decision is theirs.

The parents are performing their religious duties and "Dharma".  It is left to the adult daughter to take a decision.  Except meeting the parents and convincing them for performing the marriage or convincing your girls friend for a registered marriage, you have no other business to involve in other's matters.

I agree with the opinion and advise of expert Mr. Ibrahim Deshmukh.