Silly cake question.....

I would have thought that a 9 inch would be fine for 14 people but the 12 inch will have more impact. If like me you love cake then any leftovers won't go to waste. It depends on whether photo's of the cake cutting etc are important to you.

I would go for 12. Then you will have plenty to go around and it will look better I think than a 9 in photos I think. Xx

Tbh they are odd sizes, is there a reason she only offered you these 2?

My MIL owns her own cake company and she starts from a 4'' all the way up to a 16''. She can do bigger but not normally needed. And they normally go up in 1 inches

it also depends whether your going for a round or square cake

this is a rough guide that she shows people if it helps

I don't think you can ever have too big a cake personally. But that may just be me! As it's a wedding cake, I'd go for the bigger of the option, but maybe a different size now! Good luck!