Hi! I agree with
@nightbefore to get Vintage size. Then you can match it with the pendant or 20 motif and it won't be too much. The Magic earring is pretty, but there is a risk it might look like two big fat giant bright blue four leaf lucky charm clover on each side of your face, and you may not wear it often. Maybe try on Magic Malachite earrings as it will give a similar look except green. It's going to either be love at first sight, or hmm... might be a big too much color against my face (you'll know immediately is my guess). Blue Agate and Malachite in a Magic earring is not as neutral on the face as MOP or oynx. I think a Magic MOP is beautiful if you want a Magic earring.
Also, I recall the reason why Blue Agate is not offered in earrings is due to the stone transparency, and if they made earrings, you could see through the post which VCA felt was not aesthetically pleasing. I may be dreaming this up (I do dream a lot about VCA and make up pieces

), but you may want to first check with your SA to see if a Blue Agate earring is even an option.
So exciting! I love Blue Agate, and I hope one day, they will offer it in WG.