Should be fine if the consent was given before
she got drunk.
Nope. Not the way it works. Legally speaking, intoxication removes consent. If she gave consent then became intoxicated and then you had sex, it would still legally be considered non consensual.
Quite simply, if someone gets it into their head to make a false accusation, there’s basically no way to prove it was consensual, short of literally filming every single second you spend together. Even if you got written and video consent and made a video of the sex taking place, they could argue duress, or intoxication, or whatever. Basically, the only way this is ever going to get better is for things to get so completely out of hand that people just stop making false accusations simply because dating and having sex has become completely impossible, and even then, there will still be crazy people who do it.
So yeah, any time you have sex with someone, you’re taking a risk. That has always been the case and always will be. Just part of life. If you’re unwilling to take that risk, just don’t have sex ever again.