OP,
Collect evidence of your relationship, then apply for a fiance visa when she is back in the states.
It’s easy to do, don’t get hung up on the immigration limits etc, it doesn’t count in this case.
I’ve been through it and still going through it now. ILR application is due in April and even though there is no reason to worry about it, I do. Especially with a sprog on the way.
Don’t stress about it, don’t get sucked into the xenophobic crap, it’s an easy process to try.
You could try for a settlement visa based on her being a partner, but it’s a nightmare to prove, so go fiance first.