If you wait until you're hired, a firm might pay for your education/capstone/testing costs, saving you several thousand dollars.

I'd really suggest getting some experience first because (a) you'll need that anyway before you can use the marks and (b) what if it turns out you hate being an advisor? A lot of wasted time and money.

It's great you have the time to study now, but that doesn't have to be targeted toward the CFP specifically - since you're in school you could maybe audit some accounting or other courses, do an extra minor, something like that to broaden your horizons - that's an opportunity that will never be so accessible to you as it is now.