(50+ years old talking, so you know ;)
In France we have this saying “La bave du crapaud n’atteint pas la blanche colombe” (toad’s spit can’t reach the white dove), meaning no matter how naughty someone is they simply cannot hurt you, you're so much above them and you're so pure.
- Like others have already said: you're not a failure. You're a young man that’s just starting his adult live.
- Be aware that some parents may have a hard time seeing their innocent little daughter dating someone. And they can make the ‘date’ pay for that.
- There is also the fact that, no matter how old and how successful you will ever be, most people you will meet will have some idea about who you are and what you're worth as a person, even before they get a chance to really know you. We all do.
- And then, many people are mean. They're also plain stupid (no matter how many diplomas they've hanged on the walls of their study) and most of them are incredibly coward too, like really, and impotent (not sexually, I mean it more like they lack any willingness to fight and to endure a fight). So, the moment they think they face someone weaker than them (that's what they think, doesn't mean they're right), aka someone they can bully or belittle without much risk for them, they'll show who they really are: mean assholes.
What kind of weaker person would they show that to? I don't know, say, they may consider the dude that is dating their precious daughter is rather unlikely to punch them in the face, or to tell them they should learn to behave like adults and not brats (and, imho, that dude better not do any of that) ;)
You could probably very easily outplay them at their own stupid game but, imho, the best option is to completely ignore them. You're dating their daughter, not her parents.
Don't waste any more of your time with them. You're still very young but, believe me, time is precious and it flies so fucking fast. That girl likes you? And you like her? Enjoy being together and forget about their parents being assholes (the world is literally filled with assholes, I'm sitting on one while I'm writing this ;). And maybe it's time you start considering getting a small place of your own, so you can be together without any parents to ruin your time together? That could be worth it ;)
I don't think being 'non-religious' mean we should give up on words used religious people.
Believers in one god or another don't own those words. Non of them. They belong to all of us. They're words that belong to our common vocabulary and language. Nobody should be allowed to claim any ownership and exclusive usage.
If we start creating different vocabularies depending one's own system of beliefs, if we start limiting the use of certain words to certain groups of people (religious or, say, related to this or that specific color), where will that end? And then what common ground will we have remaining? What common language? How will we be able to keep on discussing together if we don't share the same language?
To use a Biblical reference, do we really want to create a new Tower of Babel and... are we that pretentious we think can act like if we were a god ourselves? God damn, I certainly don't. Heck, no. Fuck that.
That's just my 2 cents, obviously.