I do have some advice - don't wait, but don't exactly go all the way either.

Tell her to hold it in while you start - her kegals will reward her later.

Start by licking the labia slowly on the outside of her vagina - do this for 5-10 minutes gently with your tongue. This will allow her to transition from intercourse to oral as well.

Then after 10 minutes push your tongue between her labia and into her vagina - dart it in and move it up towards her clit. At this point some will come out - lick and suck on it. Funny thing - after the first 10 minutes (1) you won't be as squeamish (2) she will be FAR more into it and (3) the taste will be mixed with hers.

You can reposition (she can sit on your face and let it all out, or lie on her side and go slower)...or you can just continue "cleaning" her and using your tongue inside her vagina and towards her clit (but don't focus on it).

After another 10 minutes (your 20 in now) you can use a finger inside her vagina, find the spongy G-Spot (anatomically called the Skenes Gland) on the anterior wall and pull it towards you ("come hither motion"). You don't have to be gentle with your finger tip - point hard at it with your finger tip but go gentle with the flat of your tongue on her clit in a swirling motion, alternating between sucking and moving it in a circle.

She will climax very well for you.

And after that 30 minute post-sex cunnilingus...somethin g happened...instead of you focusing on the ejaculate, you focused on a whole routine which would pleasure her that happens to include eating her "creampie".

She'll like it, and you're no longer focusing solely on it.

Give it a go - everyone wins.