Prenuptial agreement question

Can a prenuptial agreement "protect" me against any credit card debt incurred by my fiance either before or after we are married? My fiance has a good amount of credit card debt (~15k) that I recently found out about. All the cards with the debt are in her name. We came up with a plan for her to tackle the debt, but in the event she continues to accumulate debt into the marriage, I'd like to be protected. Our finances are generally split, aside from a joint checking and savings which we use to pay joint expenses. I don't suspect anything will go wrong with the marriage, but I am a saver and she is a spender, so if something did go wrong, I don't want to be impacted by her irresponsible spending.

I am also wondering if my retirement accounts can/will be protected for similar reasons. She works and has her own accounts, but i am more focused on saving for retirement and don't want money that I saved to be "up for grab"s.

Lastly, what is the most cost effective way to obtain one (provided it can protect me the way I'd like)? I'm still a graduate student, so money is a bit tight. I'd prefer to not have to eat into my savings more than I need to.

Thank you in advance.