Still quite new to this keto-thing, but I understand there’s an important distinction - and some cross-currents - to be drawn between IF fasting windows and coffee (without or without any fat sources in it).
If you’re new to keto (2 weeks?), it might be advisable to NOT worry at all about fasting windows. Let your body become fully keto-adapted first … while keeping your carbs restricted (e.g., <20g/day) and maintaining a prudent level of protein (based on your lean body weight), then eat as many of those delicious fats as you have a genuine hunger for … whenever that hunger might arise!
The more you get your metabolism solidly into the fat-burning (ketone-producing) stage, and your brain and vital organs and muscles get reoriented to burn the ketones rather than the glucose from carbs, the better results you’ll get with EVERYTHING else you do inside your keto eating habits.
There’s a time and place for fasting (either intermittent or longer duration), but I would suggest to you that the first and most critical thing to do - upon which all other measures depend - is to get yourself into that fat-adapted state which typically takes several weeks to a month or more. For women, it often takes longer than for men.
So… eat (fat), drink (fat), and be merry. Enjoy that coffee with whatever you like in it (other than carbs) at whatever time of day you wish. There’ll be plenty of time to try out things like IF and other add-on measures to further enhance progress along your longer term goals.
Best of luck!