Hello Jellodude, welcome here to the forum.

Concerning your question. Normally with online connection / relationship the golden rule is 'don't send money'

In your case you have met already and her family. On the balance of probability you should have formed an opinion.
P17k is not a big amount of money. You can quite easily decide IF you want to do it or not. I'm sure you have some way to get hold of the money.
The thing is you say you just don't have it...............so the only answer is that you just can't send it.

If you want to consider a loan, then that's leading you up another level.
No reason at all why you shouldn't want to help your gf, after all you're already considering a more serious future together.

IF you can actually get hold of the money why not pay the school fees directly? That way you know they're due and you know they've been paid.
I've done this many time with extended family members.

I should warn you though that in my case there have been times when the school knew nothing about any fees. You should be prepared for that.

Don't give away any money without knowing where it's going and why.