She's 14, not 20.
She is a child. Just because she's not 8, doesn't mean that she's not a young child.
Too soon for dating ( Even though she'd sneak and probably do it anyways)
This is a guy of a few weeks..
She doesn't need to go over there...especially not overnight.
Recipe for disaster, and very concerning..
(Even though she'd probably sneak and go over anyways without your permission)
Even if you were to meet the parents. They may be lax parents, and may be absent and perhaps provide more liberties than you'd be comfortable with.
It doesn't matter if she were to be embarrassed. You are her parent and should act accordingly.
Face to face meetings... not just one and done...multiple.
Supervised visits...
The best you can do aside from the above is have the sex, focus, respecting herself, consent, body image, relationships, peer pressure and contraception talk, etc... Take her to the doctor's to get on birth control, condoms, etc...
You can't watch her 24/7.
She's going to do what she truly wants, regardless. She's going to find ways to do what she truly wants.
I also suspect that you'll be preparing a talk about heartbreaks soon.
Hope it turns out for the best.