Tough first date question

In my 30s and starting to date again. Something came to mind as a scheduled date gets closer (this weekend)

Not to say that no one deserves the benefit of the doubt, but I can't just assume a girl doesn't have any STDs no matter how great she seems, and I'll just assume that not everyone is going to be upfront about it if they do have them.

So, to try and clear the air and promote peace of mind.. what would be a polite way to ask a someone if they are clean? If there is a polite way

EDIT: I'm seeing many responses saying something to the effect of "Just wait until you're actually about to have sex".

I'm not here to judge or be judged on dating practices, I'm not expecting sex on the first date but I also want to be prepared for it if the date goes really well and sex does happen on the first date.