There's seriously no way to know that because I have no idea how big your head is or how big your ears are. Do you have calipers or a good ruler with a MM measurement to tell me how many mm's they are across?
Then it's definitely more than a carat. A 7 is around 1.25-1.3 and 8 is about 2ct
This is me wearing the 1ct./2ct. (in between) illusion earrings.
I suppose a diamond cannot be big enough,
but in my opinion are your current earrings perfect.
The size is in perfect harmony with your ear and your earlobe.
I would not go for bigger earrings.
Keep it as it is, it looks great.