Is it wrong to have sex the first day you meet a girl?

It depends on how you feel about each other.  And how you have come to live your life.  In particular, sometimes older people know more about themselves, and judge their friends better than they did when they were younger. 

It's called ONS 

Yes And no

I think you should have ethical and moral standards. I think sex is better for after marriage but that is neither here nor there. Just maybe wait a while 

only if she says no............

not wrong, but maybe she's doing the same thing with other dudes. 

Well...to me it depends on the setting.  I had sex with plenty of girls when i was younger who i only met earlier in the evening, it was just sex and they were fine with it.  It’s only wrong if you rape her

If she's willing and consents, no.  It's up to the two of you to make this decision together.

The little head is all for it. The large head should be smarter than the little head.

That's entirely up to the girl.  However, pressuring her into it doesn't count.

yes you must wait until marriage

only holding hands for you young man